https://www.t-mobile.com/news/tmo-tuesdays-free-tacos -if you’re a T-mobile customer you can get a Free Tqco at Taco Bell every week. –Update
This is live now, they will give you a Free Taco Bell Seasoned Beef Crunchy or Soft Taco every week that you can redeem through the TacoBell.com website as a pickup order at participating U.S. Taco Bell locations.