Wholesale costs of food and drink, being what they are, I estimate Taco bell is making about 45-60 cents per order, depending on the main purchase (there are 5 options), and that includes labor costs. They obviously made a great deal with Doritos (probably 30 cents a bag).
Volume, volume, volume.
Some businesses are actually smart, and lower the price of things to attract customers. And when the customer appreciates the value, they come back.
Some of you really need a Business Management course.
McD's and Burger King are selling a kid's meal for $3-4. If you had 2 or 3 kids, and needed something quick on the run, where would you go?