As a buyer, $200 or less seems to be a good price. There are a lot on here for $250 and up usually. I bought mine for $100 from another venue, in great condition. There are still deals to be found, but they are few and far between.
As a seller, $150 and up seems to be fair. The world is full of cheapskates and suckers, and everything in between. Start high and leave room to negotiate, especially on this board. There are a lot on here for $250 and up usually. Patience will get you more money, but if noone shows any interest, your price is probably too high. If you want to sell it quick, price it low.