How to find cards selling under comps on eBay

What "under comps" means, why graded cards get listed below their sold prices on eBay, how to comp one, and the free site and iPhone app that shows every listing under comps live.

By Cardboard Terminal · 2026-10-21

"Under comps" is hobby shorthand for a card priced below what the same card, in the same grade, has recently sold for. A PSA 10 that has been closing around $350 and is sitting at a $250 Buy It Now is $100 under comps. On eBay these listings exist every hour of the day; the problem is that they are buried in tens of thousands of fairly priced ones and the good ones last minutes. This guide covers what comps are, why cards end up under them, how to check one yourself, and how to have a free tool do the watching for you.

What a comp actually is

A comp is a completed sale of the same card in the same grade. Not the same card raw, not a PSA 9 when you are pricing a PSA 10, and not an asking price. eBay's sold listings are the main source for most cards, with accepted Best Offers (which eBay hides behind a strikethrough) and other marketplaces filling in. The useful number is not the last sale but the middle of the recent ones: one high sale from a bidding war or one low sale from a 4 a.m. ending should not set the price. Cardboard Terminal uses the median of the newest sales in that grade, which is the same thing an experienced buyer does by eye. See how to read a card price chart for the details.

Why cards end up under comps

• Auctions that end at the wrong hour. A seven-day auction closing at 3 a.m. Eastern on a Wednesday gets a fraction of the bidders a Sunday-evening close gets. Fewer bidders, lower hammer. Most under-comps auctions are timing, not luck.
• Titles buyers cannot find. A slab listed without the set name, with a misspelled player, or with the wrong year never shows up in the searches other buyers run. The deal finder reads the grading label on the slab instead of trusting the title, so these surface.
• Stale pricing. Sellers who price off what the card did six months ago can be well under the current market after a run-up. Sellers clearing inventory in bulk tend to list the whole lot at round numbers.
• Quick Buy It Nows. A seller who wants cash today lists under the last sale on purpose. These are the fastest-moving listings on eBay; a sharp one is gone in seconds, which is why alerts beat browsing.

How to check a listing yourself

1. Search eBay for the exact card, year, set, card number and grade. Tick Sold Items in the filters.
2. Ignore the highest and lowest result and read the middle of the last five to ten sales. That is the comp.
3. Check the cert number on the grader's site so the slab in the photo is the slab you are buying. The cert check guide walks through it.
4. Compare the listing's price, plus shipping, to the comp. Anything under about 80% of the comp is worth a look; under 70% is rare on liquid cards and usually has a reason (a qualifier on the grade, a damaged case, a non-English card).

Doing this for one card takes a minute. Doing it for every graded sports and Pokémon listing that appears on eBay is not something a person can do, which is where the tools come in.

The tool that shows cards under comps live

Cardboard Terminal's deal finder is a free, live feed of graded card auctions and Buy It Nows on eBay, each one shown next to its recent sold comps and sorted by discount and closing time. It covers graded sports cards (baseball, basketball, football, hockey and soccer), graded Pokémon and other trading card games, and sealed Pokémon product. Each row shows the listing's price as a percentage of the card's recent sold median, so a card at 71% is 29% under comps. New Buy It Nows show up within minutes of being listed; auctions are refreshed more often as they get close to ending.

The iPhone app adds alerts: pick a player, set or card and a discount threshold, and it notifies you when a listing under comps appears, so you see the $250 PSA 10 before the people who are browsing. Both the site and the app are free; the site earns a small commission from eBay when a purchase follows a click, at no cost to the buyer.

The filters that matter for under-comps hunting are the discount cap (start at 80% of comps), a minimum price so the feed is not full of $12 cards, and the sport or game you collect. The sports card page and the Pokémon page open the feed with those presets.

Other ways people do it

• Price-guide deal lists. Some paid price guides email a daily list of Buy It Nows under their average sale price. Useful, but a daily email is hours behind a live feed, and auctions are not covered.
• Browser extensions. These overlay sold comps on an eBay listing you are already looking at. Good for judging one card; they do not find the listings for you.
• Saved eBay searches. Free and simple, but eBay matches titles, not slabs, and sends one email a day per search.

What under comps does not mean

A card under comps is not automatically a buy. Comps built on two sales are noise, and a price well under them on a card that sells twice a month means a thin market, not a bargain. The deal finder hides comps that are too volatile to trust and flags low-volume cards. Check the seller's feedback and returns policy, confirm the cert, and prefer cards you would be happy to hold if the flip does not come.