Amazon is accepting used, fully functional iPhones from AT&T, Sprint, and Verizon. As with most trade-in services, you must specify whether your model is in acceptable, good, or like-new condition. That dictates the amount you'll get in return.
For example, my AT&T iPhone 4S 32GB is in perfect working order, with no visible signs of use and all the original materials included (earbuds, sync cable, box, etc.). What's more, I haven't personalized it in any way (i.e. engraving). Assuming Amazon agrees with my assessment, I'll get a gift card worth $455. If the iPhone was merely in "good" shape, with normal signs of wear (including light scratches on the body), I'd get $386.75.
Another example: a Sprint iPhone 4 8GB fetches up to $230 if it's like new, $195.50 if it's good, and $69 if it's merely "acceptable."... [Read more]