A special thanks to commenter "tamade" for pointing out the obvious. Since AT&T's unlocked iPhone 3Gs will cost you $599 (8GB) or $699 (16GB), you are better off signing a contract and canceling it than buying an unlocked iPhone. In fact, it's even cheaper to buy a 16GB iPhone using this method than to buy and unlock an 8GB version. But math isn't our strong suit so go ahead and double-check our calculations. We won't be offended:
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