Frequently Asked Questions | Trading Card Database (tcdb.com)
How are prices on this site determined?
All site prices are submitted by members based on actualized sale prices. If you click on a price, you can see a breakdown of the prices that were submitted to make up the displayed price. The site uses a median calculation to determine the totals that are displayed. If there isn't a median, then it takes an average.
Prices are included on the site to give members a ballpark idea of how much certain cards are worth and do not represent a certified valuation.