Match the card before comparing the price
Record the year, set, card number, parallel or variant, language, grader and grade. A raw card, a different parallel and a different grading label aren't interchangeable comps.
Separate individual-card sales from lots that include other items. Check whether shipping is included. If only one close match exists, describe the valuation as uncertain rather than averaging unrelated cards to create a confident number.
Asking price and sold price are different
An active listing shows what a seller wants. A completed transaction is better evidence of what a buyer paid, although one sale still doesn't establish what your card will sell for.
eBay says Product Research reports actual sold prices, including accepted Best Offer amounts. That's useful when a listing's original asking price differs from the deal. Record the tool and observation date used for your estimate.
Work through a small comp set
Hypothetical example: three genuinely matching sales are $42, $47 and $51. Their mean is about $46.67 and their median is $47. Neither figure guarantees your next sale; inspect timing and differences before choosing an estimate.
If you model a $47 sale with $6 selling costs and $4 shipping that you pay, net proceeds are $37. An advertised $47 card value is not a $47 cash return.
Compare platform FMV with your evidence
PrizePicks says it sets FMV using data from independent third-party providers. A platform estimate can differ from your matched comps because its method, timing or input data differ.
When an advertised repack EV depends on inflated card values, the calculation can look attractive even if its probability arithmetic is correct. Keep the valuation evidence beside the odds and compare a range of plausible prices.