Updated
How we research prices
Underpriced puts numbers on things: what an item sells for, what a platform takes, what you keep. This page explains where those numbers come from, when you shouldn't lean on them, and how we write the guides on this site. If something here doesn't match what you see, tell us.
The short version
- Values come from recent sales of the same item, not from asking prices.
- Every result says what it's based on and how many sales it found, so you can judge it yourself.
- Fees come from each platform’s own fee pages, and our guides say when we last checked them.
- No one pays to appear in our guides, and we don't use affiliate links.
Where a value in the app comes from
- 1
We identify the item
From your photo, barcode or listing screenshot we work out what it is: brand, model, size or pattern, era, and the condition we can see. A clear photo of the tag, label or maker's mark makes the biggest difference, so add one when the item has it.
- 2
We look for recent sales
We search sold listings, mostly from the last 90 days, on eBay, plus Poshmark and Mercari when there are enough of them. Current listings show up too, but only as competition. An asking price isn't a sale.
- 3
We keep only the same item
Sales of a different model, version, size run or era get set aside. So do lots, "for parts" listings, empty boxes and locked phones, unless that's what you're checking. Sales in the same condition as yours count for more than the rest.
- 4
We set a value and a range
We start from what the item looks like it should be worth, then let the matching sales pull the number toward what buyers actually paid. The more matching sales we find, the more the sales decide. You get a range, not just one number, and the result tells you what the range is based on.
- 5
We take off the costs
Profit is what’s left after the platform fee for that category, payment processing, shipping and your buy price. For eBay US sales we estimate shipping from the item’s likely packed size and weight at published USPS rates, and you can always enter your real cost instead. It’s profit before income tax, and you can add a tax estimate in the result.
If you work in Canadian dollars, pounds, Australian dollars or euros, we convert with the European Central Bank’s daily reference rates, and the result says when a value comes from US sales.
How to read the labels on a result
Every value comes with a short label saying what it's based on. Here's what each one means and what to do about it.
Verified sold: "Based on 12 verified sold matches."
The value rests on recent sales of this exact item.
What to do: This is the strongest kind of result. If the item is worth a lot, open the sold listings anyway.
Sold prices for similar items
We found sales of close relatives, not this exact item.
What to do: Check that the differences (size, version, year) don’t matter for yours.
Sold results need review
We found sales, but they didn’t pass our checks, so they didn’t move the value.
What to do: Look at those sales yourself before you trust the number.
Not enough recent sales of this exact item to show.
There weren’t enough matching sales in the last few months.
What to do: Treat the value as a starting point and search sold listings over a longer stretch.
Current market sources
No matching sales, but current listings and market pages back up the estimate.
What to do: Fine for setting a list price, weaker for deciding what to pay.
Photo-based estimate
We couldn’t use sales data, so the value comes from identifying the item alone.
What to do: Don’t buy on this alone. Check sold listings first.
Data confidence: 72%
How sure the result is, given your photos and the evidence we found. It appears with every label.
What to do: A low number usually means a clearer photo of the tag, label or mark would help.
On the free plan you see how many sales we found, with their titles and dates. The sold prices themselves are on paid plans.
When to double-check us
A value is a starting point, not a promise. Take a second look in these cases:
- Rare or one-off items
- With only a sale or two, one odd price moves everything.
- Condition we can’t see
- Stains, chips, repairs, missing parts and smells don’t show up in a photo.
- Possible fakes
- Matching a label isn’t authentication. Big-ticket brands deserve a closer look before you pay.
- Big local items
- Furniture and appliances usually sell locally for less than shipped sales suggest, and shipping them is rarely realistic.
- New or trending items
- Prices for new releases and viral items move faster than a few months of sales can show.
- Lots and bundles
- A value is for one item. Selling ten together is a different calculation.
To check any value yourself, our free eBay sold listings search builds a sold-only search in one click.
How our guides and free tools are made
Fees and policies come from the source
Our fee guides and calculators are written from each platform’s own help pages. Where a guide states a fee, it links that page and says when we last checked it, like "eBay fees verified Oct 1, 2026".
We update when platforms change
When Whatnot moved to tiered seller fees on Sept 21, 2026, we rebuilt the Whatnot fee calculator and corrected the guides that still quoted the old flat rate.
We use AI to help, and we check its work
Our guides are drafted and edited with the help of AI tools. Fees, dates, prices and identification facts are checked against a primary or specialist source before we rely on them, and a guide’s "Updated" date changes only when its facts change. Some older guides were written before we worked this way. We’re going through them, and the corrections below are part of that.
No made-up experience
We don’t write "we tested" or "I sold 47 of these" unless it happened. In September 2026 we removed invented stories from older guides; if you find one we missed, tell us. When we compare our own app with another, we say that we make Underpriced.
One short FAQ that matches the page
Each guide has a single FAQ of four questions or fewer, answered in the article itself.
What we don't do
Affiliate links or paid placements. Nobody pays to be included in, or ranked in, our guides and comparisons.
Sell your data. We never sell your photos or listings. If we publish market statistics, they’re combined from many users and can’t identify anyone. Terms of use
Appraisals. A value is an estimate from recent sales, not a certified appraisal for insurance, estates or taxes.
Recent corrections
Whatnot seller fees
Updated to the tiered rates that started Sept 21, 2026, including 0% commission on the part of eligible orders above $1,500.
eBay fees
Most categories are 13.6% plus $0.40 per order. Some guides still said 13.25%.
USPS shipping names and prices
First-Class Package became Ground Advantage in July 2023. We replaced the old name and prices across our shipping advice.
Vestiaire Collective fees
A flat 12% commission plus 3% payment processing, not the tiered rates we used to describe.
PSA grading prices
Updated to the current tiers: Standard $59.99, Priority $79.99, Express $199.
Collectibles facts
Removed Fiesta pieces listed in colors they were never made in, corrected which Levi’s jackets are the Type I and Type II, and fixed Hummel and CorningWare dates.
WorthPoint pricing
WorthPoint now sells one All Access plan on the web. Our review had the older three-plan pricing.
Found a mistake?
Email us the page link and what’s wrong. If you’re right, we fix it, update the page date, and add it to the corrections above. We read every message.
support@underpriced.app