A friend of mine is going to spend a year in the US. Since she stays there for just that single year, it would be quite useless getting a 2 year plan from at&t or Verizon or w/e.Are there any options using your UNLOCKED iPhone in the US, either by going for pre-paid or using a plan that will expire after one year (in case those plans exist)? She'd be likely using text and data, and maybe pay as you go calling. I'd really appreciate links to carriers! Thanks in advance.