The cheapest food that I know of, that is actually not completely junk, is spaghetti. I make the sauce myself, which makes it extremely cheap (tomato sauce + olive oil + some herbs) and the spaghetti themselves are cheap as well. Don't know the exact price, but it's hard to undercut.
You're a dog! Now I want spaghetti for dinner. I'm sure that the price I'll pay for all the ingredients needed will surpass yours. I'm now going to Walmart and will pay for the items separately. I'm sure it'll be over U$15.00, of which I'll take a pic of the receipt and post it here in about an hour. The only items I have on hand are salt, pepper, onions, oregano, and basil. I may or may not purchase grated Parmesan cheese.
Haha, I'm glad I did and I'm sure you will enjoy! You can definitely make spaghetti both ways, ultra-cheap and high-class. Sounds great, I'm looking forward to the pics. Btw, did you know that (natural) tomato sauce is healthier than fresh tomatos? Anyways, enjoy!

US28.01 was the total. Incorporated is Hunts tomato sauce of various flavors and one real tomato. Yes, even a pear. It's slow cooking on high in a crock pot. Will be ready in about four hours. Yummy!
I did purchase Parmesan cheese, but forgot to restock on bay leaves. I bought lean hamburger. The whole mushrooms go in later.
Before heading to the store, I informed an elderly man neighbor what to expect for dinner tonight. When I returned, he passed me some petite sweet orange peppers to augment the sole large yellow pepper I purchased, thinkin' that'll be enough.