I recently purchased Beckett online for a month for 3 of the 4 sports (not baseball) to price my collection. (I will get baseball for a year when those expire...)
Anyways I was going through my Barry Sanders cards, of which I have 700+, and looking up some of the better ones, when I saw an SP Authentic that was #d to 25 on the front. I know SP is some of the pricier cards out there, but I looked it up and it's worth $250! I don't remember how much I paid for it originally, but it wouldn't have been more than $20.
Also had a Tom Brady rookie with Giovanni Carmizzi (sic?) that I thought was only worth a couple bucks was worth $20.
Finding a card is worth 10x what you originally thought....priceless
Anyone have other experiences like it?