Ok, so my daughter wants an iPhone to replace her existing phone, which is broken. All she wants it for, is for making calls, texting and the iPod functionality. I want to get an iPhone off eBay, or similar site, but am a bit confused as to what exactly I should be looking for. Since we already have AT&T, I don't think I need to buy and unlocked phone. There are 2G, 3G and 3GS iPhones available, but I'm not sure if an existing AT&T sim card will fit in which model.
Any feedback would be greatly appreciated.