[ft28jags]

Don't forget shilling
The

eBay is not the ONLY place people buy/sell cards. In fact a lot of people look at eBay as an outlet to quickly sell cards. There are other places online like COMC, Beckett Marketplace, SportLots and other places to buy/sell cards. Also, card shows and card shops are another great place to buy and sell. Thus eBay pricing is just one part of the equation that determines book value. The biggest problem with eBay pricing is that you have to take all sorts of stuff into consideration starting with fixed price sales vs auctions. For fixed price sales did the item sell quickly or take a while to sell, as that might tell if the card was priced about right or priced too low/high. For auctions, everything matters from end time, length of auction, seller feedback, shipping cost, starting bid, etc. Thus the reason the same card might sell for $10 and the same day also sell for $25, and the next day sell for only $1.
Heck, I buy certain cards off eBay all the time because I know I can sell them for significantly more either by relisting them differently or selling them locally. So you have to be careful when looking at eBay as a price guide (it is a good reference point, but just like Beckett is not the end all when it comes to value).