# Trading card sale prices: how we collect them

> The Boogie Data API and MCP server are launching soon. Reports, fee calculators and methodology on this site are live now.

**For card dealers pricing inventory and collectors checking a card's value.** Our card prices are completed sales from public auction and marketplace results, recorded with the sale date, price, currency, grade and grading company the listing states. Each price keeps a price basis, because some venues do not say whether the buyer's premium is included.

## What a sale row holds

The sale date the listing states, the price as published, the currency, the sale type (weekly auction, premier auction or fixed price), the grade as printed in the title, and the certificate number when the listing shows one. A certificate number is copied as published and never inferred from a link.

## Price basis

A hammer price, a price with buyer's premium and a fixed price are different numbers. Every price carries a basis label. Where the venue does not say whether its premium is included, the label says so, and we do not adjust the price.

## Comparable sales

The card and comic value search (opening with the API) will compare up to 20 recent sales of the same card, grading company and grade. When there are fewer than three, it will add sales at other grades, adjusted by a fixed step of 1.5 times per grade point, and give recent sales more weight (a sale's weight halves every 180 days). When there are no matching sales it will say not enough evidence instead of producing a number. Different print runs of one card can be grouped together. We will publish the method and its back-test result with the tool.

## What we leave out

Seller and buyer names and handles are never kept. Sales we cannot match to one card and grade stay out of comparisons.

## Related

- [Sold price](/glossary/sold-price/)
- [Price basis](/glossary/price-basis/)
- [Grade](/glossary/grade/)
- [Certificate number](/glossary/certificate-number/)
- [Grade population](/glossary/grade-population/)
- [Comparable sale](/glossary/comparable-sale/)
- [Realized price](/glossary/realized-price/)
- [Lowest ask](/glossary/lowest-ask/)
- [All methodology](/methodology/)