There’s No Such Thing as a "Free" iPhone 7, Even If Carriers Offer You One
7, along with discounted versions of higher storage models and the iPhone 7 Plus. There’s just one problem: all of them require you to keep the phone and your contract for 24 months and require you to trade in a newer phone, like an iPhone 6 or 6s. T-Mobile calls this a “no-cost 24 month finance agreement.”
Basically, you’re giving the carrier your old phone for the privilege of getting an iPhone 7 with no up front cost. However, if you leave the carrier within those two years, you have to pay off the phone, minus what you’ve been credited. If you leave you do not get your old phone back, nor do you get any sort of credit for your old phone, which means that cutting out early is an extremely bad idea.