Well, if you are already a member of Beckett.com price guide, you can link your account (which I just did).
Might help for selling though, not sure, kinda hard to tell at this point, not sure how many people actually buy based on book.
Evan Longoria Supercollector!
1,199 different cards and counting!
Current Group Breaks: 5 Case '15 Bowman Draft Player Draft (Paying)