Best Buy is currently offering complimentary $50 gift cards to all customers that active a new mobile phone. The offer is valid on Verizon, AT&T, Sprint and T-Mobile phones activated with a two-year agreement at Best Buy, Best Buy Mobile or BestBuy.com. To receive the gift car customers must first register their mobile phone number, and up to four other numbers of a family plan, on Best Buy's website before February 9. All registered numbers will then be able to receive the $50 reward by activating a new phone anytime before December 31.