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I'd 100% avoid it, I use to work there, their refurbishment process is awful, we use to to get iPhones in to sell with screens popping out of the device.
 
You're better off using eBay for used. At least there you can return it if there's a problem. Gamestop lacks quality control.
 
Over Christmas I sold a bunch of iDevice stuff to GameStop due to their extra 30% promotion.

One of the items was a japanese iPhone (Softbank) and although I told the sales manager so, they still purchased it. I wonder to this day where that iPhone is as it is pretty useless in the states.
 
I got my ipod nano 6th gen from there. I've had it about 2-3 weeks and it works fine. Not sure about buying a phone from them though.
 
Why pay so much for a used item. The prices are so high only a fool would purchase from them. Shop around.
 
Another quick story: At GameStop, to receive the 30% bonus you had to purchase any used item. I did so by buying a first generation iPod nano. It worked but was fairly beat up and was cheap.
Low and behold it qualified under Apple's replacement guarantee (something to do with a bad battery, back in the day). Apple sent me a box/label/postpaid with a couple of days and within a week I had a brand new, current iPod!

Not too shabby for $18.
 
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