A friend of mine has an AT&T iPhone 4S 16GB with a terribly cracked screen. She upgraded to an iPhone 5 and her 4S is just sitting around. I'm looking to switch to AT&T from Sprint and since I want to wait until the next iPhone launches to use my phone discount I'm looking for an older iPhone right now. What's the best price to buy this from her? I think Apple will replace it for $200, which will give me a brand new phone (refurbished). That'll have a higher resale version in a few months. I can also take it to one of those screen replacement stores but I've read the front screen is a lot more difficult (more expensive?) to replace. Or would I be better off just buying one off eBay? If I do that I'm up for getting a 4, MAYBE a 3GS.