Inventory Management for Resellers: Systems, Spreadsheets & Software Guide 2026

Sarah had 300 items listed across eBay, Poshmark, and Mercari. She knew she had that vintage Coach bag somewhere—a buyer was waiting, money in hand. After tearing through six bins, two closets, and a pile of unlisted stock in her guest room, she found it: buried under a stack of jeans she’d forgotten she owned.

The sale went through. But she’d wasted 45 minutes finding one item. Multiply that by 20 sales a month, and you’re looking at 15 hours of lost time—time that should have been spent sourcing or listing new inventory.

This is the inventory chaos problem. And if you’re serious about scaling your reselling business beyond a casual side hustle, solving it is the difference between making $500/month and $5,000/month.

The irony? Most resellers spend hours researching what to buy and zero time organizing what they already have. They obsess over finding the next flip while losing money on flips they can’t locate, don’t remember buying, or accidentally list twice on different platforms.

In this guide, I’ll walk you through every inventory management option—from free spreadsheets to full accounting software—so you can find what actually fits your business stage, budget, and workflow.

In this guide, you’ll learn:

• When you actually need an inventory system (and when you don’t)
• The 4 tiers of inventory management: spreadsheets, barcode systems, reseller apps, and accounting software
• SKU naming systems that save hours every month
• Physical organization strategies for any space (apartment to warehouse)
• How to track inventory across multiple platforms without losing your mind
• The record-keeping basics that save you at tax time
• When to purge dead inventory (the 90-day rule)
• How to scale your system as you grow

Table of Contents

• Do You Even Need an Inventory System?
• Option 1: Free Spreadsheet (Best for <100 Items)
• Option 2: Barcode/QR Code System (Best for Physical Storage)
• Option 3: Reseller Apps (Best for Cross-Listing)
• Option 4: Full Accounting Software (Best for Full-Time)
• SKU Naming Systems: Why They Matter
• Physical Organization Strategies
• Tracking Across Multiple Platforms
• Record-Keeping Requirements
• Digital Photo Organization
• When to Purge Inventory: The 90-Day Rule
• Scaling Your System: The Growth Path
• Frequently Asked Questions
• Related Tools
• Conclusion: Start Simple, Scale as Needed

Do You Even Need an Inventory System?

Before we dive into systems, let’s be honest: not everyone needs one.

If you’re flipping 10-20 items a month, selling locally on Facebook Marketplace, and everything fits in one closet—a formal inventory system might be overkill. You can probably keep track of it all in your head.

But here’s the threshold where systems become critical:

The 50-Item Rule

Once you cross 50 active items, chaos starts creeping in:

Warning Signs You Need a System NOW

• You’ve accidentally listed the same item on two platforms and sold it twice (nightmare scenario)
• You can’t find an item when it sells (lost $50+ item = lost $50+ profit)
• Tax season gives you heart palpitations (no records = guessing = audits)
• You don’t know your actual profit (are you even making money?)
• You’re buying duplicates without realizing it (dead capital sitting in bins)
• Your “death pile” of unlisted items keeps growing (purchased but never processed)

If any of these sound familiar, keep reading. We’ll find the right system for you.

Pro Tip: The best time to start an inventory system is before you need one. The second best time is now—even if it means retroactively logging what you already have.

Option 1: Free Spreadsheet (Best for <100 Items)

For most beginner and part-time resellers, a simple spreadsheet is all you need. It’s free, flexible, and you can start in 5 minutes.

When to Use a Spreadsheet

• You have fewer than 100 active listings
• You sell primarily on one platform
• You don’t need barcode scanning speed
• You’re comfortable with basic Excel/Google Sheets

Basic Spreadsheet Structure

Here’s the template I recommend. You can create this in Google Sheets (free) or Excel:

Setting Up Your Spreadsheet

Step 1: Create the Header Row

Open Google Sheets (free at sheets.google.com) and create column headers as shown above.

Step 2: Format Key Columns

• Format columns E, I, L, N, O, P as Currency
• Format columns D, H, K as Dates
• Create a dropdown for Status (Listed/Sold/Unlisted/Returned)
• Create a dropdown for Category (Clothing, Electronics, Home, etc.)

Step 3: Add Formulas

Net Profit formula for column P:

=IF(L2="","",L2-E2-N2-O2)

Step 4: Create Summary Section

Add a summary area that auto-calculates:

• Total items purchased this month
• Total items sold this month
• Total profit this month
• Average profit per item
• Average days to sell

Spreadsheet Pros and Cons

Pros:

• ✅ Completely free
• ✅ Total flexibility to customize
• ✅ Works offline (Excel) or syncs everywhere (Google Sheets)
• ✅ Easy to share with accountant at tax time
• ✅ Can export to other systems later

Cons:

• ❌ Manual data entry takes time
• ❌ Easy to make mistakes or forget entries
• ❌ Not connected to selling platforms
• ❌ No photo attachment (without workarounds)
• ❌ Gets unwieldy past 200-300 items

Google Sheets Template Features

A well-designed reseller inventory spreadsheet should include:

1. Inventory Tab - All items with full details
2. Dashboard Tab - Key metrics at a glance (total inventory value, profit this month, items listed)
3. Monthly Summary Tab - Track performance month over month
4. Category Analysis Tab - See which categories are most profitable
5. Platform Analysis Tab - Compare eBay vs Poshmark vs Mercari performance

Pro Tip: Use conditional formatting to highlight items that have been listed for 60+ days (turning them yellow) or 90+ days (turning them red). This flags stale inventory that needs price drops or removal.

BONUS: Downloadable Template

Want a head start? We’ve created a free Google Sheets inventory template specifically for resellers. It includes:

• All columns mentioned above
• Pre-built formulas for profit calculation
• Dashboard with key metrics
• Conditional formatting for stale inventory
• Category and platform dropdowns
• Monthly profit tracking

Download Free Inventory Spreadsheet Template (Make a copy to your own Google Drive)

Option 2: Barcode/QR Code System (Best for Physical Storage)

If you have 100+ items and spend too much time searching for products in your storage area, a barcode or QR code system can save hours every week.

How It Works

1. Create unique labels for each item (SKU printed as barcode or QR code)
2. Attach labels to items or bins
3. Scan to look up item location, details, and photos
4. Scan when sold to automatically mark as sold and delist from other platforms

Equipment Needed ($50-150)

Option A: Budget Setup ($50-75)

• Phone with camera (you already have this)
• Barcode/QR generator app (free)
• Label printer paper + regular printer
• Or: Avery labels for inkjet printers

Option B: Semi-Pro Setup ($100-150)

• Dymo or Zebra thermal label printer (~$100-150)
• Continuous thermal labels ($15 per roll, lasts ~500 labels)
• Barcode scanner ($25-40) - faster than phone camera

Option C: Full Pro Setup ($200-300)

• Dedicated barcode scanner
• Thermal label printer
• Dedicated tablet for inventory management
• Professional inventory software subscription

Barcode vs QR Code: Which Is Better?

My recommendation: QR codes for resellers. They can link directly to your listing URLs, item photos, or a Google Sheet row—more useful than just a number.

Setting Up a QR Code System

Step 1: Generate QR Codes

Use our free QR Code Label Generator or create QR codes that link to:

• Your spreadsheet row for that item
• A Google Drive folder with photos
• The live listing URL

Step 2: Create Label Template

Design labels with:

• QR Code (links to item info)
• SKU in human-readable text
• Brief item description
• Purchase date
• Bin/location number

Step 3: Print and Apply

Print labels on adhesive paper or thermal labels. Apply to:

• The item tag (for clothing)
• A sticker on the item (for electronics/home goods)
• An attached card (for fragile items)
• The bin containing the item (for bulk organization)

Step 4: Scan Workflow

When working with inventory:

• Listing new item: Create label → Attach → Add to spreadsheet
• Finding item: Scan QR → See location → Retrieve immediately
• Item sold: Scan QR → Mark sold → Remove label → Ship

Barcode System Pros and Cons

Pros:

• ✅ Find any item in seconds (no digging through bins)
• ✅ Faster processing at scale
• ✅ Professional appearance
• ✅ Reduces errors (scanning vs manual entry)
• ✅ Great for family/team operations

Cons:

• ❌ Upfront equipment cost ($50-200)
• ❌ Setup time for existing inventory
• ❌ Labels can fall off or fade
• ❌ Overkill for small operations (<100 items)

Pro Tip: If you’re testing the barcode approach, start with free QR codes and regular paper labels before investing in a thermal printer. Make sure the workflow actually improves your efficiency before upgrading equipment.

Option 3: Reseller Apps (Best for Cross-Listing)

If you sell on multiple platforms (eBay, Poshmark, Mercari, Depop, etc.), dedicated reseller apps offer inventory tracking plus cross-listing in one package.

Top Reseller Apps Compared (2026)

List Perfectly

Pricing: $29/mo (Basic), $59/mo (Business), $99/mo (Pro)

Best Features:

• List once, publish to 11+ platforms
• Built-in inventory management with location tracking
• Business analytics and profit reporting
• Image editing tools
• Bulk editing and relisting

Best For: Full-time resellers with 200+ active listings who sell on multiple platforms.

Limitations: Monthly cost adds up; learning curve for setup.

Vendoo

Pricing: $12/mo (100 listings), $20/mo (250), $30/mo (500), $50/mo (1,000)

Best Features:

• Intuitive cross-listing interface
• Good mobile app
• Basic inventory tracking
• Profit analytics by platform
• Auto-delist when item sells (some platforms)

Best For: Part-time resellers who want cross-listing without complexity.

Limitations: Basic inventory features compared to List Perfectly.

Crosslist

Pricing: $29/mo (Pro), $39/mo (Max)

Best Features:

• Fast, simple cross-listing workflow
• Import existing listings from platforms
• Chrome extension for quick listing

Best For: Sellers focused primarily on cross-listing speed.

Limitations: Limited inventory management features; not a full inventory system.

Should You Pay for a Reseller App?

The math:

If you cross-list to 4 platforms manually:

• Time per listing: 15-20 minutes (unique photos, descriptions for each)
• At 50 listings/month: 12-17 hours

With a crosslisting app:

• Time per listing: 5-7 minutes (create once, publish everywhere)
• At 50 listings/month: 4-6 hours

Time saved: 8-11 hours/month

If your time is worth $20/hour, that’s $160-220 saved monthly. A $30/mo app pays for itself 5x over.

When NOT to pay:

• You only sell on one platform
• You have fewer than 30 active listings
• Your time isn’t the bottleneck (sourcing is)

Reseller App Pros and Cons

Pros:

• ✅ Cross-listing saves massive time
• ✅ Automatic delist when sold (prevents double sales)
• ✅ Professional analytics and reporting
• ✅ Photo storage and editing built-in
• ✅ Designed specifically for resellers

Cons:

• ❌ Monthly subscription costs ($144-1,200/year)
• ❌ Learning curve for new software
• ❌ Dependent on app reliability (outages happen)
• ❌ May not integrate with accounting software
• ❌ Feature overlap with what platforms already provide

Pro Tip: Most reseller apps offer free trials (7-14 days). Try two different apps before committing. The best app depends on which platforms you prioritize and your workflow preferences.

Option 4: Full Accounting Software (Best for Full-Time)

If you’re a full-time reseller treating this as a real business (or want to), proper accounting software provides inventory tracking plus everything you need for taxes, financial reporting, and growth planning.

Top Accounting Options for Resellers (2026)

QuickBooks (Self-Employed or Simple Start)

Best For: Resellers with $30K+/year in sales who want professional books

Key Features:

• Automatic bank feed imports
• Expense categorization
• Mileage tracking (for sourcing trips)
• Quarterly tax estimates
• Receipt capture via phone
• Inventory tracking (Simple Start and above)
• Profit & Loss reports

Cost: $15/mo (Self-Employed), $30/mo (Simple Start)

Why Resellers Like It:

• CPA-friendly (accountants know QuickBooks)
• Grows with your business
• Easy quarterly tax payments
• Integrates with payment processors

GoDaddy Bookkeeping

Best For: eBay and Etsy sellers who want automatic transaction import

Key Features:

• Direct import from eBay, Etsy, Amazon, PayPal
• Auto-categorizes expenses
• Tax schedule estimation
• Simple profit/loss reporting
• No manual entry for sales

Cost: $5-15/mo

Why Resellers Like It:

• Set it and forget it for eBay sellers
• Very affordable
• Minimal manual work
• Good for tax preparation

Limitations:

• Less robust than QuickBooks for complex businesses
• Limited inventory features
• Doesn’t support all platforms (no Poshmark import)

Wave Accounting

Best For: Budget-conscious resellers who want free accounting

Key Features:

• Invoice creation
• Expense tracking
• Bank connections
• Basic financial reports
• Free (makes money on payment processing)

Cost: Free

Why Resellers Like It:

• You can’t beat free
• Covers the basics well
• Good for testing if software helps before paying for QuickBooks

Limitations:

• Limited inventory management
• No payroll
• Support is minimal (free product)
• Fewer integrations

When to Upgrade to Full Accounting

You should consider full accounting software when:

Pro Tip: Many resellers use a combination: a crosslisting app for inventory/listing management (Vendoo or List Perfectly) plus QuickBooks or Wave for accounting. They don’t need to be the same tool.

Accounting Software Pros and Cons

Pros:

• ✅ Real financial reporting (know your actual profit)
• ✅ Tax preparation made easy
• ✅ Bank integration reduces manual entry
• ✅ Scales with your business
• ✅ Professional documentation for loans, etc.

Cons:

• ❌ Monthly cost (free options exist but limited)
• ❌ Learning curve
• ❌ May not understand reselling nuances
• ❌ Overkill for casual sellers
• ❌ Inventory features are secondary to accounting

SKU Naming Systems: Why They Matter

A SKU (Stock Keeping Unit) is a unique identifier for each item in your inventory. It’s how you find item #247 instantly instead of saying “that blue Nike jacket from three months ago.”

Why You Need SKUs

Without SKUs:

• “Where’s that vintage Pyrex bowl?”
• (Searches bins for 20 minutes)
• “Which Patagonia jacket sold—the blue one or the teal one?”
• (Checks multiple platforms, cross-references photos)

With SKUs:

• “SKU 0115-KIT-003 sold. That’s Bin 2, Kitchen items, third item purchased on January 15th.”
• (Retrieves item in 30 seconds)

The Perfect SKU Formula

A good SKU tells you at a glance:

1. When you bought it
2. What category it belongs to
3. Which specific item it is

Formula Option 1: Date + Category + Number

[MMDD]-[CAT]-[###]

Examples:

• 0115-CLO-001 = January 15th, Clothing, first item
• 0115-CLO-002 = January 15th, Clothing, second item
• 0118-ELC-001 = January 18th, Electronics, first item

Why this works: You can instantly see how old an item is (January vs. August) and what category it’s in without looking it up.

Formula Option 2: Source + Date + Number

[SOURCE]-[MMDD]-[###]

Examples:

• GW-0115-001 = Goodwill, January 15th, first item
• SA-0115-001 = Salvation Army, January 15th, first item
• ES-0120-001 = Estate Sale, January 20th, first item

Why this works: If you source from multiple places and want to track which sources produce the best ROI.

Use our free SKU Generator to create consistent SKUs automatically.

Category Codes

Standard 3-letter codes make SKUs readable:

SKU Best Practices

1. Be consistent - Once you pick a format, stick with it. Mixing formats defeats the purpose.

2. Keep it short - 10-12 characters max. You’ll be typing and reading these constantly.

3. Make it meaningful - A SKU should tell you something without looking it up.

4. Avoid special characters - Stick to letters, numbers, and dashes. Slashes and spaces cause problems in some systems.

5. Start day one - Don’t say “I’ll add SKUs later when I have more inventory.” You won’t.

Pro Tip: Print your SKU on item labels AND include it in your listing description. When an item sells, the eBay notification will include the SKU—you’ll know exactly which bin to grab without clicking through.

Physical Organization Strategies

Your inventory system is only as good as your physical organization. If SKU 0115-CLO-001 is “somewhere in the guest room,” you still have a problem.

Small Space Organization (Apartment/Closet)

Space available: A closet, corner of a room, or under-bed storage

Strategy: Maximize vertical space and use clear bins

Equipment:

• Clear plastic bins (see contents without opening)
• Over-door organizers (for accessories, small items)
• Garment rack (if you sell clothing)
• Shelf risers
• Label maker or tape + marker

Organization System:

1. Bin by category:

   • Bin 1: Clothing (small items)
   • Bin 2: Electronics & accessories
   • Bin 3: Home goods
   • Bin 4: Ready to ship (sold items)

2. Label everything:

   • Each bin has a number
   • Spreadsheet tracks: SKU → Bin Number
   • Can find any item in 30 seconds

3. Rotation system:

   • New items go in front
   • Old items pushed to back
   • Monthly review of items not selling

Real Example:

Sarah runs a $2K/month Poshmark business from her apartment closet:

• One rolling garment rack: 50 clothing items
• Three stackable bins: shoes, accessories, ready-to-ship
• Total space: 4 feet × 3 feet
• Organization time: 15 minutes when listing new items

Medium Space Organization (Garage/Spare Room)

Space available: Half a garage, spare bedroom, or basement area

Strategy: Create zones and implement a bin numbering system

Equipment:

• Industrial shelving (Costco/Home Depot, $50-100 per unit)
• Clear bins or labeled opaque bins
• Folding table for processing/packing
• Garment racks for clothing
• Good lighting (garage fluorescents are insufficient)

Organization System:

1. Create zones:

   • Zone A: Unlisted inventory (death pile, needs processing)
   • Zone B: Listed inventory by category
   • Zone C: Packing station with supplies
   • Zone D: Ready to ship

2. Aisle + Shelf + Bin numbering:

   • A-1-3 = Zone A, Shelf 1, Bin 3
   • B-2-5 = Zone B, Shelf 2, Bin 5

3. Color coding by category:

   • Blue bins: Electronics
   • Green bins: Clothing
   • Yellow bins: Home goods
   • Red bin: Rush orders / recently sold

Real Example:

Mike runs a $4K/month eBay business from half his garage:

• Two industrial shelving units (6 shelves each)
• 24 medium-sized bins (numbered A1-A12, B1-B12)
• Rolling garment rack with 100+ items
• 6-foot folding table for photography/packing
• Shipping station with scale, label printer, supplies
• Total investment: ~$300 in organization equipment

Large Space Organization (Warehouse/Dedicated Room)

Space available: Full garage, warehouse space, or dedicated room

Strategy: Implement SOP (standard operating procedures) and potentially barcode scanning

Equipment:

• Full industrial shelving systems
• Pallet racking (for large items)
• Climate control (important for vintage items, electronics)
• Professional lighting for photography
• Dedicated photography area with backdrop
• Packing station with multiple shipping options
• Potentially a wheeled cart for picking orders

Organization System:

1. Warehouse layout:

   • Receiving area: Where new sourced items enter
   • Processing area: Cleaning, photographing, listing
   • Storage area: Organized by category or turn rate
   • Shipping area: Packing supplies, scale, label printer
   • Returns area: Items being processed for return/refund

2. High-velocity vs. slow-mover sections:

   • Fast sellers near the front (less walking)
   • Slow sellers in the back
   • Review and rotate monthly

3. Pick lists and batch processing:

   • Print all sold orders together
   • Pick all items at once
   • Pack in batches
   • Drop off at once

Scaling Consideration:

At 500+ active items, consider:

• Hiring help (VA for listing, family member for packing)
• Batch processing (list 20 items at once, pack all sold at once)
• Dedicated photography setup (consistent lighting = faster photos)

Pro Tip: Whatever your space, maintain a “sold items” zone separate from active inventory. When something sells, it moves immediately to this zone for packing. This prevents the panic search when you can’t find sold items.

Tracking Across Multiple Platforms

The cross-listing dream: list once, sell everywhere, double your exposure.

The cross-listing nightmare: item sells on eBay, you forget to delist from Poshmark, now you’ve sold the same item twice.

The Cross-Listing Problem

When you sell on multiple platforms without an integrated system:

• Double sales: The same item sells on two platforms within hours
• Manual delisting: Every sale requires logging into 3-4 platforms to remove listings
• Price inconsistency: You lower the price on eBay but forget about Mercari
• Tracking chaos: “Did I sell this on Poshmark or Depop?”

Solution 1: Manual Platform Tracking (Free)

For sellers on 2-3 platforms with <100 items

Add these columns to your spreadsheet:

• Platform 1 Listed? (Y/N/Sold)
• Platform 2 Listed? (Y/N/Sold)
• Platform 3 Listed? (Y/N/Sold)

Workflow:

1. List item on Platform 1 → Mark “Y” in spreadsheet
2. Cross-list to Platform 2 → Mark “Y”
3. Item sells on Platform 1 → Mark “Sold” and change Platform 2 to “Delist”
4. Go delist from Platform 2 → Mark “N”

Time required: 3-5 minutes per sale for delisting

Solution 2: Browser Tabs Workflow

Keep all platforms open in dedicated browser tabs:

1. Get sale notification (email or app)
2. Switch to browser with all platform tabs pinned
3. Search item by title or SKU on each platform
4. Delist immediately
5. Update spreadsheet

Time required: 2-3 minutes per sale

Solution 3: Crosslisting Apps (Paid)

Apps like Vendoo and List Perfectly offer automatic or semi-automatic delisting:

How it works:

1. Create listing in app
2. App publishes to all connected platforms
3. Item sells on one platform
4. App automatically delists (or prompts you to delist) from others

Time required: 30 seconds per sale

This is the strongest argument for paid crosslisting software—not the listing speed, but the delisting automation that prevents double sales.

Platform-Specific Notes

eBay: Most flexible for SKUs (add to custom field), best for price changes

Poshmark: Limited search functionality, harder to find items to delist quickly

Mercari: Good search, allows SKU in description

Depop: Poor inventory management tools, best for low-volume sellers

Facebook Marketplace: No real inventory system, mark as sold manually

Pro Tip: Always include your SKU in every listing description (at the bottom, where buyers won’t see it). When an item sells, you can search your other platforms by SKU to find and delist quickly.

Record-Keeping Requirements

Good records aren’t just about organization—they’re about taxes, performance analysis, and protecting yourself.

What to Track for Every Item

Purchase Information:

• Purchase date
• Purchase price (including tax)
• Source (store name, address)
• Receipt image (for tax deduction documentation)

Listing Information:

• List date
• List price
• Platforms listed on
• SKU
• Storage location

Sale Information:

• Sale date
• Sale price
• Sale platform
• Buyer info (kept by platform, but note username for problem buyers)
• Shipping cost
• Platform fees
• Payment processing fees
• Net profit

Why You Need This:

The 2026 Tax Reality for Resellers

As of 2026, you’ll receive a 1099-K from any platform where you had $600+ in sales. This isn’t new income—it’s income that was always taxable. But now it’s being reported to the IRS.

What this means for your records:

1. You MUST track cost basis - Without proof of what you paid, the IRS assumes $0 cost (all sales = 100% profit)
2. You MUST track expenses - Shipping, supplies, mileage, platform fees are all deductible
3. You SHOULD track by platform - Match your records to each 1099-K

Use our Tax Deduction Calculator to estimate your deductions and the Reseller Taxes Guide for complete 2026 tax information.

Receipt Management

Digital receipt method:

1. Take phone photo of every receipt immediately after purchase
2. Save to dedicated Google Drive folder (named by date: “2026-01-15 Goodwill”)
3. Include receipt cost in spreadsheet
4. At tax time, receipts are organized and ready

Receipt app method:

• Apps like Expensify, Receipt Bank, or QuickBooks mobile
• Snap photo, auto-extracts vendor and amount
• Syncs to accounting software

Pro Tip: No receipt? You can reconstruct records with bank/credit card statements. But actual receipts are stronger documentation if audited. Spend 5 seconds photographing every thrift store receipt.

Digital Photo Organization

You take 10 photos per item. At 100 items, that’s 1,000 photos. At 500 items, you have 5,000 photos clogging your phone and laptop.

Without organization, finding old photos for relisting, returns, or disputes becomes impossible.

Folder Structure

Option 1: By Date

Photos/
  └── 2026/
      ├── 01-January/
      │   ├── 0115-sourcing-goodwill/
      │   │   ├── 0115-CLO-001/
      │   │   ├── 0115-CLO-002/
      │   │   └── 0115-ELC-001/
      │   └── 0118-sourcing-salvation-army/
      └── 02-February/

Option 2: By Category

Photos/
  └── Inventory/
      ├── Clothing/
      │   ├── 0115-CLO-001-patagonia-fleece/
      │   └── 0118-CLO-003-levis-jeans/
      ├── Electronics/
      │   └── 0120-ELC-001-ps4-pro/
      └── Home/
          └── 0122-HOM-001-pyrex-bowl/

Option 3: Flat by SKU (Simplest)

Photos/
  └── Inventory-2026/
      ├── 0115-CLO-001/
      ├── 0115-CLO-002/
      ├── 0115-ELC-001/
      └── 0118-CLO-003/

Filename Conventions

Don’t leave photos as IMG_4892.jpg. Rename to include:

[SKU]-[item-name]-[photo-number].jpg

Examples:

• 0115-CLO-001-patagonia-fleece-01.jpg
• 0115-CLO-001-patagonia-fleece-02-tag.jpg
• 0115-CLO-001-patagonia-fleece-03-flaw.jpg

Why this matters:

• Search by SKU finds all related photos
• Search by item name finds related items
• Tag and flaw photos are identified without opening

Cloud Storage Options

Recommendation: Google Drive for most resellers. It integrates with Google Sheets, syncs across devices, and 15GB free handles ~3,000+ items before needing to upgrade.

Photo Workflow

When photographing new items:

1. Create folder: [SKU]-[brief-description]
2. Take all photos, save directly to folder
3. Add folder name/SKU to inventory spreadsheet
4. Upload/sync to cloud

When item sells:

• Keep photos for 90 days (return period plus buffer)
• After 90 days, archive to “Sold-2026” folder or delete

When item is relisted:

• Photos are ready in organized folder
• Reuse without re-photographing

Pro Tip: Google Drive and iCloud automatically sync phone photos. Set up a dedicated “Inventory” album on your phone. Photos taken in that album sync to a specific folder without manual transfer.

When to Purge Inventory: The 90-Day Rule

Dead inventory isn’t just annoying—it’s costing you money. Storage space, mental energy, and capital tied up in items that won’t sell.

The 90-Day Rule

The rule: If an item hasn’t sold in 90 days despite active listing and appropriate pricing, take action.

Why 90 days?

• Enough time for seasonal cycles and buyer discovery
• Not so long that you’re warehousing junk forever
• Aligns with quarterly review cycles

Signs It’s Time to Purge

The Purge Framework

Step 1: Flag items at 60 days

Use conditional formatting in your spreadsheet to highlight items approaching 90 days. This is your warning.

Step 2: At 90 days, choose an action:

Option A: Price Drop (15-25%)

• Item has views and interest
• Still believe it will sell
• Price drop may trigger watchers

Option B: Platform Switch

• Not selling on eBay? Try Mercari or Poshmark
• Different audiences, different results

Option C: Bundle

• Combine with related items at a discount
• “Vintage kitchen lot - 3 Pyrex bowls”

Option D: Auction

• Start at your break-even price
• Let the market decide true value

Option E: Donate

• No offers, no interest, no hope
• Get the tax deduction and free up space
• Mental health value of decluttering

Option F: Local Sale

• Facebook Marketplace local pickup
• Garage sale
• Consignment store

What to Do with True Dead Inventory

If nothing works after 120 days:

1. Donate and deduct - Get a receipt, deduct fair market value on taxes
2. Lot it on eBay - “Mystery box” or “vintage lot” at extremely low prices
3. Give to friends/family - At least someone enjoys it
4. Garage sale - Last chance at any money
5. Throw away - If it’s truly worthless, cut your losses

Pro Tip: Track your purge rate. If more than 10% of items are being purged, you have a sourcing problem—you’re buying things that don’t sell. Tighten your buying criteria.

Scaling Your System: The Growth Path

Your inventory system should grow with your business. Here’s the typical progression:

Stage 1: Hobby (1-50 items)

Revenue: Under $500/month
System: Mental tracking + basic notes
Time on organization: 1 hour/month

What you need:

• Phone notes or simple list
• Dedicated box or bin for inventory
• Bank account that separates reselling income

Don’t worry about:

• Spreadsheets
• Software
• SKUs
• Complex organization

Stage 2: Side Hustle (50-150 items)

Revenue: $500-2,000/month
System: Spreadsheet required
Time on organization: 2-4 hours/month

What you need:

• Google Sheets inventory spreadsheet
• Basic SKU system (date + number)
• Organized bins or shelves
• Labeled storage locations

Consider:

• Simple photo organization (folders by SKU)
• Receipt tracking for taxes

Stage 3: Serious Side Income (150-300 items)

Revenue: $2,000-4,000/month
System: Spreadsheet + crosslisting app
Time on organization: 4-6 hours/month

What you need:

• Comprehensive spreadsheet with all data points
• Crosslisting app (Vendoo or similar)
• Physical organization system
• Photo workflow
• Basic accounting or good records for tax prep

Consider:

• QR code/barcode system
• Dedicated storage space
• Batch processing workflow

Stage 4: Part-Time Business (300-750 items)

Revenue: $4,000-7,500/month
System: Crosslisting app + accounting software
Time on organization: 6-10 hours/month

What you need:

• List Perfectly or equivalent
• QuickBooks or dedicated accounting
• Barcode/QR system for retrieval speed
• Dedicated workspace with zones
• SOPs (standard operating procedures)

Consider:

• Hiring part-time help (listing, packing)
• Dedicated photography setup
• Multiple shipping carriers/options

Stage 5: Full-Time Business (750-5,000+ items)

Revenue: $7,500+/month
System: Full inventory management software + accounting + potentially custom solutions
Time on organization: 10-20 hours/month (or staff handles it)

What you need:

• Enterprise crosslisting tools
• Full accounting suite (QuickBooks Online or similar)
• Warehouse-style organization
• Pick/pack workflow optimization
• Staff or virtual assistants

Consider:

• Custom inventory software
• Amazon FBA for some inventory
• Wholesale or bulk sourcing channels

Growth Triggers: When to Level Up

Upgrade your system when:

Frequently Asked Questions

What’s the best free inventory system for resellers?

Google Sheets is the best free option. It’s flexible, syncs across devices, and you can customize it exactly for your needs. Combine it with Google Drive for photo storage and you have a complete free system that handles up to 300-500 items before getting unwieldy.

Should I use the same SKU across all platforms?

Yes, absolutely. The whole point of a SKU is one identifier per item across your entire business. Include your SKU in the listing description on every platform (at the bottom, not visible to buyers). When something sells, you can search other platforms by SKU to delist quickly.

How do I track inventory I haven’t listed yet (death pile)?

Create a separate section or tab in your spreadsheet for “Unlisted” items. Track:

• When you bought it
• What you paid
• Why it’s not listed (needs photos, needs cleaning, waiting for right season)
• Target list date

Set weekly goals to reduce the death pile. If items sit unlisted for 30+ days, either list them immediately or accept they’re never getting listed and purge them.

What information should be on a physical inventory label?

At minimum: SKU and location. That’s enough to look up everything else in your spreadsheet.

Better: SKU, brief description, purchase date, bin location

Best (with QR code): QR linking to full item record, plus human-readable SKU

How often should I reconcile my inventory?

Monthly at minimum for serious sellers. Quarterly for casual sellers.

Reconciliation means: checking that items your spreadsheet says you have actually exist, updating items marked as sold, removing items that were purged or returned.

Full physical inventory counts are recommended annually or semi-annually for 200+ item operations.

Do I really need accounting software, or is a spreadsheet enough?

Spreadsheet is enough if:

• You’re making under $10K/year in revenue
• You’re comfortable manually calculating taxes
• Your sourcing is simple (one credit card, receipts saved)

Accounting software is worth it if:

• Revenue exceeds $20K/year
• You want accurate profit reporting
• Multiple payment methods and sourcing channels
• You want to spend zero time on taxes (software + CPA handles it)

How do I handle returns in my inventory system?

1. When return is initiated: Mark item as “Return Pending” in spreadsheet
2. When item arrives back: Inspect condition
3. If resellable: Put back in inventory, change status to “Listed” or “Relisted”
4. If not resellable: Mark as “Donated” or “Disposed” and record the loss
5. Update financials: Original sale → return = net $0 (or loss if you paid return shipping)

What’s the best label printer for resellers?

For starting out: Any inkjet printer + Avery labels (cheap, works fine)

For scaling up: Dymo 4XL (~$100-150) for shipping labels or Dymo LabelWriter 450 (~$70-100) for inventory labels. Thermal doesn’t need ink, so long-term cost is lower.

For high volume: Zebra or ROLLO thermal printers (~$150-250)

How do I track inventory across eBay, Poshmark, Mercari, and Facebook Marketplace?

Manual method: Spreadsheet columns for each platform (Listed Y/N, or listing URL)

Semi-automated: Use a crosslisting app that shows all active listings in one dashboard

Best practice: Always include SKU in every listing. When item sells, search other platforms by SKU to delist within hours of sale.

When should I hire help vs. investing in better systems?

Invest in systems when:

• You’re doing the same manual tasks repeatedly
• Software can automate what you’re doing manually
• Your bottleneck is process, not capacity

Hire help when:

• You’re maxed out on time but have more profitable work to do
• Tasks are simple enough to delegate (packing, photographing)
• Your hourly rate on high-value work exceeds cost of help ($15-25/hour)

Rule of thumb: System investments pay off over months (one-time cost, ongoing benefit). Hiring pays off immediately (trade money for time this week).

Related Tools

These free tools work alongside any inventory system:

• SKU Generator - Create consistent SKUs automatically
• QR Code Label Generator - Generate QR codes for inventory labels
• ROI Calculator - Calculate profit before you buy
• Tax Deduction Calculator - Estimate tax savings from deductions
• Fee Calculator - Compare platform fees before listing

Conclusion: Start Simple, Scale as Needed

Here’s the truth about inventory management: the best system is one you’ll actually use.

A complex barcode system does nothing if you’re too overwhelmed to maintain it. A fancy spreadsheet is useless if you never open it.

Start with the minimum viable system for your current scale:

• Under 50 items? Mental notes and a basic list are fine.
• 50-100 items? Simple spreadsheet with SKUs and locations.
• 100-300 items? Full spreadsheet + physical organization + photo system.
• 300+ items? Consider paid tools, accounting software, and batch workflows.

The goal isn’t perfect organization—it’s not losing money to chaos.

Every minute spent searching for sold items, double-selling on platforms, or panicking at tax time is a minute you could spend sourcing better inventory or living your life.

Pick a system that fits where you are today. Use it consistently for 30 days. Then evaluate: what’s working? What’s a pain point? Adjust accordingly.

Your future self—the one running a $5K/month operation—will thank you for starting now.

Ready to get organized but don’t want to build from scratch?

Grab our free Google Sheets inventory template with all the columns, formulas, and conditional formatting discussed in this guide.

Download Free Inventory Template

Related Guides:

• Thrift Store Flipping Complete Guide - Everything about sourcing profitable items
• Reseller Taxes 2026: Complete 1099-K Guide - Tax requirements and deduction strategies
• The Real Cost of Flipping - Understanding all your costs

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