For $2, the Duo includes a Beefy Crunch Burrito and a medium fountain drink (the combo features Taco Bell-exclusive Mtn Dew Baja Blast but you can also get any other fountain drink). If you just want the burrito, it's being sold for $1.49 (may vary).
The Beefy Crunch Burrito features Flamin' Hot Fritos, warm nacho cheese sauce, seasoned ground beef, reduced fat sour cream, and seasoned rice, wrapped up in a warm flour tortilla.
It was first introduced in 2010 and has been brought back several times since. The Beefy Crunch Burrito has been popular enough to spawn a Facebook fan page numbering over 70,000 followers.
Photo via Taco Bell.