Looking for a used iPhone for my dad. He has tmobile, but that narrows my search. I know AT&T will work if it's unlocked, but what about Verizon? If so, will vzw have to be unlocked too?
What kind of iPhone? I know the iPhone 5s will.
Something cheaper like a 4S or a 5
The 4S will not work. A 5, 5S and 5C will (they're unlocked).