Following a back and forth between T-Mobile and AT&T on promotions geared toward customers wanting to jump the carrier ship, AT&T announced today a short term promotion that actually rewards existing customers in addition to new users.

AT&T is shelling out $100 (in the form of a credit) for new lines including smartphones and tablets.

New and existing customers are eligible when you activate a qualifying wireless line

Add a new line for any smartphone, feature phone, tablet, wireless home phone, MiFi puck, or other connected device

You must remain active and in good standing for 45 days; your credit will be applied within 3 bill cycles

The promo runs through the end of March, so it’s not permanent, but it’s certainly a hefty incentive and hopefully of sign of what carrier competition can bring.