an error/variation going through cards in your PC? How about discovering one at show/eBay/store unbeknownst to the owner? I once bought a group of cards on eBay that included the '57 Baker Bakep ERR which netted me $300
as I had no interest in that card. I recently found a couple '69 Dawlryple and McClendon VAR in a large lot I bought. Last were some '72s with the end letters being green I think instead of yellow (from eBay). The '69 and 72s only added a couple extra bucks value but they were still fun to find on accident...How about you??