Hamburger helper. If you've got the metabolism of a squirrel, use sausage in a tube for extra flavor. Otherwise, stick with lean ground beef. Sinks in your stomach and stays there for many hours. Calorie dense. If you use the sausage, costs less than four dollars for four meal's worth of food.
When I was a broke "dropped out of college before going back and finishing" waiter, and living with some friends, we made up something we called insta-meal.
1 box of kraft macaroni and cheese
1 lb of ground beef
1 packet of taco seasoning mix
cook the mac and cheese according to the box directions; sautee the meat, drain the fat, and add the seasoning mix until combined; combine mac and ceese with taco meat for homemade hamburger helper that tastes WAY better than the boxed sh*t.