Chef Boyardee, some of them are really good, sometimes, if you want to flavor it up even more, add a little bit of black pepper. Just make sure you get them when they are a dollar each, CRAZY DEAL
If you bum with a few friends, a can of tomato sauce, a pound of whatever pastas, a big can of chilli beans and sometimes, if you have the money, a fresh vegetable of your choice that you add to the mix. This whole meal is really good tasting and about 1,50$ each. I've been eating it all summer.
Also, rice or couscous(better tasting than rice IMO) with tuna, a fresh vegetable added to the mix and soy sauce. That's crazy good too.
Just remember to have a few spices with you while cooking, they add some flavour because it isn't your mom's meat loaf after all. Personnaly, I like chilli and five colour pepper with a grinder.
And remember to not eat too much ramen noodles as a meal, they can be ok for a snack but I find them pretty sketchy to eat as a meal too often(once in a while, DAMN it's good).
My final words would be to drink a lot of water because these meals countains usually lots of salt and it's easy to get dehydrated.
Happy bumming or whatever cheap eating situation.
R.I.P. Saucer Boy
May your snowblades be with you wherever you are