Things to Know: Using Comps to Accurately Value Your Cards

One of the most important parts of buying or selling sports cards is knowing how to read and use comparable sales, or “comps.” Comps show you how a particular card, or the closest match to it, has sold in the past. This helps to determine its current market value. Not all comps are created equal, and understanding these nuances will help you avoid overpaying or underselling while keeping you informed in the hobby. Here are some factors to keep in mind when using comps to price cards.

Recency Takes Priority

This first one should go without saying; the most recent sales are the most important ones. Card values can shift quickly based on a variety of factors, so looking at the latest transactions gives the clearest picture of a card’s current value. That said, if a player, set, or the overall sports card market experiences a sudden spike or drop, even the newest comps may not fully reflect the true value until additional sales take place.

This 2018 Saquon Barkley Gold Kaboom in a BGS 9.5 sold for a record $20,820 in Alt Auctions.

This exact same card sold for just $5,500 on eBay just one month prior.

That is over a $15,000 jump in price.

This is the second highest ever sale for any Saquon Barkley card.

Sell… pic.twitter.com/XcAaQqObaH
— Alt (@altxyzofficial) August 25, 2025

Fixed Price vs Auction Sales

It’s important to know the difference between auction sales and fixed price sales. Auction results usually give a better idea of a card’s market value because multiple bidders help set the price, while fixed price sales only show what one buyer paid and what the seller accepted. For example, if a card normally sells for $800 at auction, a $1,000 fixed price sale doesn’t mean it’s suddenly worth $1,000. One buyer may have just wanted it without waiting for another auction. Likewise, if a card is listed at $1,000 as a fixed price and sells right away, it only shows the card is worth at least $1,000, not that the market caps it there. Fixed price sales can still be useful, but keep this in mind when trying to determine a card's value.

Listing Details

When using comps, it’s also important to look beyond just the final sale price and check the listing details. For example, if a graded card sold at auction on eBay for a surprising price, start by looking at the auction’s end time, since listings that close at odd hours might get fewer bidders. Check the condition of the graded slab. Chips, cracks, or older labels can affect the final price, even if the card inside is in great shape. Shill bidding, where someone bids on a card without intending to pay to raise the final price, is another thing to watch for. These are just a few things that can affect a card’s comp, but looking at the listing closely often provides plenty of insight into the sale price.

Shill bidding? What do you think? Same account also did it on other listings by the same seller. #ebay pic.twitter.com/r0x9u9W245
— Josh (@JoshInPDX) October 4, 2024

Use Multiple Sales

To really understand a card’s market, look at multiple recent sales to avoid being misled by unusually high or low prices. It can also help to check sales of different grades for the same card to see if it fits with what would be expected. Using multiple sales instead of focusing on a single transaction will typically provide a more reliable picture of a card’s worth.