I have seen them for less on ebay than on the board.
Then again, the prices can vary and be all over the map.
I think there is one up for bid now for around $22 at present
Go back a few years and I remember it being a $60-80 chip or more so if you want to use that as a basis, now is the time to buy
For a better idea, you might find some information on ebay under completed auctions.
Good luck