A:AnswerYes, Best Buy will accept a trade. I was trading in an I phone 6 which is relatively old and didn't receive very much for trade in as I had anticipated.
A:AnswerIt is not an unlocked phone so I am not sure when the phones would work on the same carrier for both companies. You would probably have to contact T Mobile because as of right now I believe that Best Buy does not have service for T Mobile.