I am thinking about buying a no-contract 8 gb iphone 3gs and activating it as a go-phone with att. I have a couple of questions I would like to ask before I go about doing this. 1. Is it possible to have a data plan on a go-phone sim card? 2. If I try to activate a data plan will they cancel my account? 3. Will I need to buy a sim card cutter off ebay?