In addition, you can ask for "double wrapped," so they give you two tortillas. You can also ask for them to skew the tortillas a bit, so they are in the shape of a venn diagram rather than on top of each other. I've found that with this "hack," they will give you more food even if you don't ask for it. Well if you do... this happens: https://sphotos-b.xx.fbcdn.net/hphotos-ash4/430727_101513405...
You can basically get 2 burritos for the price of one. And don't say burrito bowls are bigger, since as you can see in the picture, the resulting burrito is larger than the basket.
This method + asking for extra everything except guac and meat is probably the highest amount of calories/$ you can get. I think it comes out to less than .4 cents per calorie, for a meal that includes most of the food groups!