[bn2cardz]

Recently it has a lot to do with population reports. For type collectors you can look for very common ones, but there are some players that very few are known. There are some that don't even have any past single card sales which support the low population reports.

If there is a player you are interested in you can look at cardtarget.com to look at past sales. VCP (vintagecardprices.com) does the same, but isn't free like cardtarget. For instance Joe Kelley has only two in the POP reports (both SGC, and there is another one not on a POP report, but is graded by PSA) there are also no sales reported on one in both Cardtarget or VCP. So when the one in Sterling Sports Auction sells this Thursday it may or may not line up with the other cards in the set that have more known examples in the hobby.