Okay so about 4 months ago my contract with my iPhone 3G ended. The phone itself was done for, alot of problems with it and physically just bad. I ended up getting a new phone, Samsung Impression and the data plan. Now about 3 months into this phone, it is having way to many problems and I just dont want to wait until the 2 years of this phones contract is up. So would it be fine to buy a used iPhone from a third party source? Would that interfere with my contact at all if i just swap out my SIM card and use it in an iPhone? I know i would probably have to get the data plan for it, i understand that. But would there be any other fees to switching phones in the middle of contract?