T-Mobiles bullish new tactics may not have made a huge change in the wireless industry just yet, but theyve certainly prompted its biggest players to take notice. ATTs latest reply is to offer T-Mobile customers up to $450 per line for switching over to its network — albeit, with a few catches. Theres also a flat $200 credit simply for switching the line, but dont expect that to cover the cost of a new iPhone: customers either have to buy a new phone at full price, activate a phone that they already own, or sign up for ATTs Next early upgrade plan, which would have you buying full-price devices anyway. ATT isnt making any two-year contract options available as part of the deal, but that may be fine for T-Mobile customers, who should be used to off-contract pricing and payments.