AT&T has announced that you will get $100 off of your bill if you add a new line to the account. This will take $100 off every new phone, tablet, or mobile hotspot that is added to the account. This deal is only good between January 29th and March 31st. The offer can be redeemed from AT&T retail stores and offers online. AT&T is also paying up to $200 to subscribers that switch over from T-Mobile.