Full Speed Slim
A look at what is currently available on eBay
How much will gamestop give me for this bundle..?
A ps2 slim
Guitar Hero 2 with guitar
Guitar Hero with guitar
Battlefield 2: Modern Combat
Star Wars Battlefront 2
Full Spectrum Warrior Ten Hammers
Gran Turismo 4
Need For Speed Underground 2
Tony Hawks Underground
Tony Hawks Underground 2.
They won't give you anywhere near what it's worth. Sell it on ebay. Although you'll want to split it up. Maybe bundle the system with a game or two, bundle the guitar heroes with their respective guitars or maybe all together. Then sell the rest individually. You'll get the most money out of it that way. And it will be cash, not store credit.
Trust me, those stores really rip you off most of the time. Of course you'll still get a good chunk of money, maybe a few hundred bucks, it won't be nearly as much as you could get for all of it on ebay.