Is it the fat PS2 or the slim one? Gamestop currently has a trade-in offer. You'll get $20 extra credit when you trade in your used hardware. It expires on the 10th of this month, so you'll probably get between $50-$70. If you missed the offer, then you should check your local pawn shops and see how much they will give you. They'll probably give you like $20 more than what Gamestop normally offers.
http://www.gamestop.com/gs/specialty/tradeins/offers.aspx









