A sports card or Pokémon card is worth what buyers have recently paid for that exact card — not what sellers are asking. Here is how to find that number, and the mistakes that make it wrong.
Use completed sales of the exact same card (same year, set, number and version), keep raw and graded apart, and take the middle price of the last month of sales.
Identify the exact card. Year (from the copyright line on the back, not the stats), brand, set, and card number (usually on the back). A 2018 and a 2019 card of the same player are different cards with different prices.
Check the version. Is it the base card or a parallel? Look at the border color and finish (refractor, prizm, holo), a stamped serial number like 25/99, an autograph or a piece of jersey. On many recent Topps cards, the last digits of the small code printed on the back identify the version. A numbered parallel can sell for many times the base card.
Look at sold listings, not active ones. Asking prices are hopes. Many listings never sell at that price. Only completed sales show what someone paid.
Keep only true matches. Throw out other parallels, lots of several cards, reprints and damaged copies. Keep raw copies with raw copies, and compare a graded card only with the same grade from the same grader.
Use the median of recent sales. Take the last 30 days, line the prices up and take the middle one. One lucky auction or one cheap sale should not set the price. If there are only one or two sales, treat the number as a rough guide, not a value.
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An asking price is what a seller hopes to get. Only completed sales show what buyers actually paid.
Look for a stamped number like 25/99 or 1/1, usually on the front near an edge, sometimes on the back. The second number is how many were made.
Compare what raw copies sell for with what graded copies sell for, minus the grading fee and shipping. CardGauge's pre-grade check does this comparison.
Some cards sell rarely. A month with no sales means there is no reliable price yet, not that the card is worthless. Check again later, or look at the same card in a nearby version.
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