If I put an ATT 3g sim card into a used iPhone will I need to sign a new contract?
I have a phone with a $10/mo unlimited data plan (non-smart phone...samsung impression) and I was hoping to buy a used iPhone and put my sim in -- will I be forced to sign a 2 yr contract (I'm in one right now)? will I be able to keep paying $10/mo or does it automatically switch to 30/mo or 15/mo? Do I need to call ATT to do this?