Are Taco's really that cheap or is Cheese that expensive

[ironworks]

Ok so once a week, I frequent Jack in the box and order my cheap lunch. 2 regular taco's and one Jumbo jack hamburger. The jumbo Jack is 1.39 without cheese and 1.79 with cheese. And the taco's are 2 for 99 cents. But get this each taco has a slices of cheese, standard. So do the taco's only cost 9.5 cents a piece? or Are they selling me the Jumbo Jack for cheap in hopes that I will add the 40 cent cheese.

What's even more funny is I never order cheese for this reason, but 1 out of 3 times I get cheese by accident.

Any insight from those much smarter then me. Back to work I have some cheese to pay for.