I'm 99% sure that you can't sell your EDGE card as it's tied to your name/address.
Just keep trying to sell it for cash, you'll get waaaaaaaaaay more for your stuff/time.
I wouldn't trust GS with that much store credit anyway. All it takes is one mouth-breathing dumbass employee to accidentally credit it to someone else or a preorder for the new Jonas Brothers DS game.
Holy shit you have no idea what you're talking about. It's not hard to determine you're not a fan of GS, not many people are, but let's quit sipping on the Haterade for a minute and let someone who knows what's up answer the OP's questions without a bias.
Anywho....here's the deal Tom
If you want cash, Kan IS correct, you'll get more for it if you sell it on your own. I understand you've not had much luck with Craigslist nor do you have the luxury of time but just for the XB360 system, a wireless controller, and the A/V & A/C cords you're looking at $80 STORE CREDIT. If you wanted cash, they shave off 20% and it'll bring you down to $64. Granted the games are different prices and that's not counting the hard drive, which is taken in separately.
As Jro pointed out, they no longer accept regular Xbox games in trade anymore and haven't since February so you're stuck with those. They will take in Gamecube games, accessories, and systems but they really do not fetch much, even for store credit.
Now if you have XB360 games and ultimately decide on getting a store credit, they do have a promotion going on currently where you get an additional $10 for every 3 XB360, Wii, PSP, PS3, and DS games you trade in. Of course trade-in values aren't that high to begin with, they usually give a 1/3 or 1/4 of what it's sold for.
If you do opt for the store credit, they'll put it onto an Edge Card and ANYONE can use it, regardless of what Kan thinks. The ONLY time your personal information matters in regards to the trade-in is at the time of the actual trade and the only reason your info is even taken is most likely because of local laws for pawn shops to prevent the buying/selling of potential stolen property. Once they hand you the card, they could give shit care less what happens to it. Spend it, Gift it, Lose it....seriously, GS won't give a flying F***. It's the same principle that applies to that card that also applies to the games before you traded them in, what you do with it is YOUR business. Obviously the one thing you can't do is try to hock the card in or around the store but I'm sure you've got better sense than that.
As for the mouth breathers employed there and their inept ability to "accidentally" put the credit in someone else's name or whatever the hell was mentioned...those kinds of things can lead to termination. It's pretty hard to fuck up a trade-in if the person is standing right in front of you with their goods. I'm not saying it's impossible....but it's pretty goddamn hard.

Additionally, it's harassment to pressure the customer into pre-ordering anything. Sure those mouth-breathers do it on every sale but the simple fact of the matter is NO means NO. If the mouth breather in question has a problem with this and won't just put the credit on a card, you get the manager on duty. If the manager has a problem, you go above him to his boss.
Lastly, I don't know what kind of market there is on gift cards/store credit cards. I have to think it's just as hard if not harder to sell the card than it would be to sell the XB360 but you might be able to find a buyer in a friend who might already have a XB360 as they could use it to get some new games or something. Regardless, hope that helps some. Good luck with selling your stuff.
