My teen daughter wants to buy herself an iPhone. She currently carries and iPod Touch and her cell phone - that is only 8 months old - everywhere she goes, and wants to reduce that to one device. Of course, we still have a year + on the contract, so we can't get a phone through ATT. She's fine with a used one, but is nervous about being taken for a ride on the purchase. What sites are best for purchase of used iPhones?