Switch To AT&T, Get $450 By Staff Reporter | Jan 05, 2014 03:04 PM EST Itâs no secret that T-Mobileâs Un-carrier initiative has been doing great things for the telecomâs subscriber base, so it should come as little surprise that AT&T is now mobilizing to steal away some of those new customers.On Friday, AT&T announced that T-Mobile subscribers willing to ditch their plan and activate on AT&T Next would be eligible to receive up to a $450 rebate per line.âBeginning Jan. 3, under the limited-time offer, T-Mobile customers who switch to AT&T can trade-in their current smartphone for a promotion card of up to $250, which can be used toward AT&T products and services. Trade-in values will vary based on make, model and age of the smartphone, but many of the latest and most popular smartphones will qualify for a value of $250,â the company said in a press statement. âT-Mobile customers can receive an additional $200 credit per line when they transfer their wireless service to AT&T and choose an AT&T Next plan, buy a device at full retail price or activate a device they currently own.â The AT&T offer is certainly a nice draw if youâre looking to switch providers anyway. If you have a spare GSM smartphone lying around that youâre willing to activate instead of buying a new one, you may well save some money on your monthly statement.As Engadget points out however, itâs important to do the math on this one since T-Mobileâs rates may still be cheaper depending on what handset you end up activating. If you want to switch to AT&T and buy a new iPhone 5 or Galaxy S4, chances are you wonât be saving too much on your bill. Still, a $450 rebate is nothing to scoff at and AT&T will likely see a good number of converts as a result of their new promotion.