I'm on T-Mobile currently but it's pretty much being used as a MP3 player. Can I just restore it, tell them I got it off eBay (which I did) and using it as a iTouch? It's a first gen, and it seems the battery isn't holding the charge well anymore. I have Applecare warranty on it from the previous owner (in the process of getting it transferred). Or if all else fails, can I just get a prepaid AT&T sim (without data of course)? or what if I use my friends SIM who also have an iPhone (with data )? In which case, does it affect his phone plan in anyway?