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Underpriced AI

How we price, and how we know

Every week we check our prices against what the items really sold for, and publish the result.

How a price is made

Five steps. The sales, the grade and the three prices are on every result page.

  1. 1

    Read the photo

    Brand, model, maker's marks, edition and condition, from the picture. When a valuable item names its model, a second pass re-reads the legible text and every disagreement is logged, so the misses teach the next version.

  2. 2

    Find real sales

    Sold-price sources, asked in order until one answers: specialist eBay sold-price API; an independent backup sold-comp service; archive of recorded sales.

  3. 3

    Keep the sales that match

    Lots, sets, bundles and the wrong variant are filtered out. A comp sold for parts counts for less. Best Offer sales are counted below their shown price. When the matches spread too wide, the confidence drops instead of the spread hiding inside a median.

  4. 4

    Price it

    A weighted median of the matched sales, corrected by a calibration learned from items that actually sold, per category and per price band. At $50 and up an AI read of those same sales against your item's condition sets the point, kept inside our range. Then three list prices, each with its two-week sell chance once enough listings like it exist.

  5. 5

    Say how sure

    A confidence grade, a range built to hold most sales, and the sold listings themselves one tap away, so you can judge the number before you trust it.

What makes it hard

Why a range exists at all, and what we do about each reason.

  • A sale is capped by the ask

    A listing cannot sell above its asking price. When a seller lists below our number, the sale lands below it too and looks like a miss.

    What we do. We grade ourselves only on sales where the seller chose their own price, and read high or low only from sales no ask could cap.

  • The photo cannot show everything

    Whether it works, what is missing from the box, a chip on the underside. Two identical photos can be two different items.

    What we do. The scan grades condition from the photo. Tap a different condition and the three prices move, and a detail you add re-runs the sold comps at no charge.

  • Some things sell for many prices

    A named maker, a rare colorway, a first edition. Vintage and art run widest, and a median of everything is wrong for the piece in your hand.

    What we do. For pottery, where sold comps made the price worse than the model's own read, the model's number is kept and the comps become a sanity band. The weekly grade says which categories should follow.

  • Comps lie a little

    A lot of six listed as one, a part sold as the whole, a Best Offer shown at its asking price.

    What we do. Matched-sale filters, a discount on Best Offer sales, and a ceiling that stops one outlier lifting the number.

  • Markets move

    Ninety days is a long time for a phone and a short time for a chair.

    What we do. Recent sales weigh more, and the weekly grade tells us when a category drifts.

How it gets better

Every Tuesday the grade below is recomputed from that week's sales. Each change to the pricing is tested against real sales before it ships and recorded the day it does.

Typical gap on sales where the seller chose their own price, by weekly report. Lower is better. Latest 40% on 214 sales.
  1. September 25, 2026

    The same photos put to other AI every week and published beside our number.

  2. September 18, 2026

    This page: the weekly grade published, wins and misses.

  3. September 14, 2026

    The AI price refiner promoted for items at $50 and up after a shadow test.

  4. September 11, 2026

    Comp pollution filters after a drone camera counted as a comparable for a bike trainer; a price now waits for the comps instead of showing a guess first.

  5. September 10, 2026

    Realisation factor: the estimate corrected by how much of our number items in that price band actually fetched.

  6. September 9, 2026

    Best Offer sales counted below their shown price, since the shown price is the ask.

  7. September 8, 2026

    Model anchor for pottery, where sold comps were making the price worse than the model's own read.

  8. September 3, 2026

    Per-category calibration learned from items that sold: the price level and the range width now come from measured sales, not a fixed margin.

The same photos, put to other AI

Each week the new sales get their first photo sent to other models with no hints and no sold data. Our number is the one the seller saw at scan time. Figures are on a $100 item.

ModelTypically off byUs, on the same salesLinked an eBay listingSales
Underpriced AIThe number the seller saw, from real sold listings$3385%78
Our model without sold dataOur prompt on the first photo, no sold listings$35$33n/a78
PerplexityThe first photo, web search on$43$3349%77
GeminiThe first photo, no sold data$30$2511%9
ChatGPTThe first photo, no sold data$37$330%76

Sales the seller reported in the last 90 days, with the photo they scanned. A model that gave no number on a sale is left out of its own count, so its row also shows our gap on exactly the sales it answered. Linked means the answer carried an eBay listing link; for us it means the scan showed sold listings. Our own model cannot link, so that cell says n/a. Junk sale prices are dropped by the same rule for every row. Updated October 5, 2026.

This week's grade

Our prices against what the items really sold for, in a reseller's words. It is written by the weekly report, not by us.

Price a $100 item with us and, half the time, it sells for between $60 and $140.

our number, $100$60$140$0$200
Measured on 214 sales in the last 90 days where the seller chose their own price. Half were closer than this, half further.
  • 4 in 10

    sales landed inside the range we showed. 6 in 10 across every sale.

  • $8

    on a $100 item is how far sellers who listed at our number ended up from it. They were asking our number, so this proves less than it looks.

  • High

    We run 2% high on sales no asking price could cap.

Where the number holds tightest

Closer than our overall gap, on a $100 item.

  • Artabout $25 off
  • Antiquesabout $30 off
  • Clothingabout $32 off
  • Collectiblesabout $34 off
  • Accessoriesabout $38 off

Where prices vary most

Further than our overall gap. The result page says so next to the price, and the comps show why.

  • Toysabout $69 off
  • Vintageabout $65 off
  • Pottery & Glassabout $53 off
  • Electronicsabout $44 off
  • Jewelryabout $44 off
  • Home & Gardenabout $43 off
The full numbers

Last 90 days, updated September 29, 2026. 408 sales measured.

Typical gap, seller priced on their own
40%

Across 214 sales where the seller did not list at our number. Half were closer than this.

Sale landed inside our range
43.5%

Of those same sales. Across all 408 sales it is 61.3%.

Typical gap, seller listed at our number
8%

Across 194 sales priced within 2% of our estimate. Flattering by construction, so it is not the headline.

On the 53 sales no asking price could cap, our estimates ran 2% high at the median.

By category

CategorySalesTypical gapInside our rangeLean
Clothing3632%58.3%Too few to say
Electronics2644%42.3%Too few to say
Pottery & Glass2453%20.8%Too few to say
Collectibles1834%50%Too few to say
Jewelry1744%41.2%Too few to say
Antiques1330%46.2%Too few to say
Art1325%53.8%Too few to say
Accessories1338%38.5%Too few to say
Vintage1065%40%Too few to say
Toys1069%30%Too few to say
Home & Garden943%33.3%Too few to say

Categories with fewer than 8 sales in the window are not named. Lean needs 15 uncapped sales before it is read.

How we measure it

  • A sale counts when you mark an item sold and enter the price, or when a listing published through us sells on eBay. We use the price the item actually fetched.
  • The gap is the distance between our estimate and the sale price, as a share of the estimate. The typical gap is the median, so half of the sales were closer than the figure shown.
  • Sellers who list at our exact number and sell at it are, in part, proving our number by using it. So the headline figure counts only sales where the seller priced on their own, and the anchored figure is shown separately.
  • Lean is read only from sales no asking price could cap, such as auctions, best offers and sales you report yourself. A listing that sells at the seller's ask cannot sell above it, so it says nothing about whether we ran high.
  • A category is named once it has 8 or more sales in the window. Smaller ones are folded into the totals.
  • The window is the last 90 days and the report runs every Tuesday.

What we do with it

When a category runs weak, the result page says so in plain words next to the price, and the comps view shows the sold listings the number came from, so you can judge it for yourself. The weekly report also feeds the calibration that sets our ranges, category by category.

See it on your own item

Your first scan is free, on web or mobile. The comps behind every price are one tap away.

Scan your first item free