There is a trade in deal at Gamerush stores (certain Blockbuster videos). The trade deal is trade in any 2 (PS1, PS2, XBox, GC or GB/GBA) games and get any preowned game for 9.99. I took 4 cheapo games I got at Circuit City (4.99 each) and traded them at gamerush using the trade deal. I got the credit for the games (total of $26) so I walked out with Spiderman 2 and Fatal Frame II and $4 in credit for $20 total purchase (not including tax). Fantastic deal...now I'm just waiting for them to get some more games I want in...like Riddick and Sudeki. I don't know how often they get games in but one of the clerks said they had over 100 games traded in last Monday. Should be a good rotation of stock.
EDIT - trade in deal only good at Gamerush areas in certain Blockbuster stores. Check out www.gamerush.com
EDIT2 - You get credit for the games you trade in and you get to use the trade 2 deal at the same time. Your credit, if it's enough, will apply towards the 9.99.
This is great for newer high dollar games like Spiderman 2, Riddick, Fatal Frame 2, Sudeki, etc. Also since there are no exclusions you can trade old sports games and other near worthless games to get in on the deal (though you will get next to no credit for credit for them).