A good example from chip economics 101. If the seller keeps putting these on the price will drop on each one. There are probably less than 20 California chip collectors who would pay $100 for a single chip. And the number who would pay $100 for a single chip where one seller apparently has 100 of them (or close to it) is much lower. I'd guess that if you offered that chip for sale at a buy-it-now of $20 both on and here on Greg's board you wouldn't sell all 100.

By the way, I don't think the seller is doing anything wrong. He's up-front that he bought the whole rack and that there were 100 of this chip. So if a few are willing to pay $100 for this chip, I say good for him.