Discount Stacking Calculator: True COGS After Tax and Rebates
Model retail arbitrage buy cost after sale discounts, coupons, sales tax, cashback, card rewards, rebates, quantity, and resale fees.
What this tool helps you do
Calculate true retail arbitrage buy cost after sales, coupons, sales tax, cashback, card rewards, rebates, quantity, and resale fees. Use the effective COGS and decision panel before buying.
Interactive inputs and calculations load after the app boots. Use this prerendered preview to understand what the tool covers before opening the live experience.
Best for
- discount stacking calculator
- coupon stacking calculator
- retail arbitrage calculator
- cashback calculator
- rebate calculator
True retail arbitrage COGS after stacked discounts
Use this calculator when the sourcing decision depends on the buy cost after checkout and delayed credits, not only the shelf price. It models sale markdowns, fixed or percentage coupons, sales tax paid, cashback basis, credit-card rewards, rebates or store credits, quantity, and a resale-price check.
The output separates checkout total from effective cost. That prevents a common reseller mistake: treating delayed portal or rebate credits as cash that is guaranteed today. The decision panel warns when credits exceed checkout, the resale comp goes negative after fees, or too much margin depends on delayed tracking.
For bookkeeping, keep receipts, coupon records, rebate screenshots, and marketplace payout records together. IRS guidance for payment reports and purchase-price adjustments makes recordkeeping important because gross marketplace payments and later offsets may not appear in one clean line item.
- Inputs: shelf price, sale percent, coupon, sales tax, cashback basis, card rewards, rebates, quantity, resale price, and platform fee.
- Output decision: copy effective COGS, skip or renegotiate, verify reward assumptions, or proceed only if rebate tracking is reliable.
- Risk prevented: overstating ROI by ignoring sales tax, delayed credits, capped coupons, or fee-adjusted resale value.
Verify the current platform fee
IRS Form 1099-K guidance
IRS guidance that gross payment reports are not adjusted for fees, refunds, shipping, discounts, or other offsets.
IRS Publication 525
IRS reference for purchase price adjustments that can reduce basis when rebates or similar adjustments apply.
Credit-card resale adjustment calculator
Internal companion tool for reward value, interest carry, and annual-fee allocation.
Frequently Asked Questions
What does the discount stacking calculator include?
It includes sale markdowns, fixed or percentage coupons, sales tax paid, cashback, credit-card rewards, rebates or store credits, quantity, and optional resale-price fee checks. The key output is effective COGS, not just what you paid at checkout.
Should cashback and rebates lower my buy cost immediately?
Only if the credit is real, tracked, and tied to the purchase. The calculator separates checkout total from delayed credits and warns when too much of the margin depends on later cashback or rebate approval.
Why does the calculator include sales tax?
Sales tax paid at sourcing is real cash out and usually belongs in the buy cost for profit modeling. If a valid resale certificate removes tax on qualifying inventory, model the tax as zero and keep the certificate and receipt evidence.
How should I use the resale-price fields?
Enter a conservative sold-comp price and expected platform fee. If the fee-adjusted resale value does not clear the effective COGS, the tool tells you to skip, renegotiate, or verify the assumptions before buying.
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