hi everybody. i am going to go to usa for a conference next week. when turning back to my country i want to buy a iphone from US. so; can i buy i iphone 3gs or iphone 4 from apple store or best buy or at&t shop without contracted? it is not important iphone will be locked or cant use with other providers. i want to just buy a iphone and come back. what will the price of a iphone 3gs 16 gb and iphone 4 16 gb ? i want to buy from a store. any opinions?