A simple and public way to gauge volume and popularity of a players sports cards. On Ebay - enter their name and click search - go to filter and under categtry choose sports mem, cards & fan shop then sports trading cards, then trading card singles - then in filter go to sold items and select that radio button - update search results - for example michael jordan has 120,000 search results - his ebay number would be 120 - anything under 1,000 would be an ebay number of 0