I lived off this one for a few months...
Can of generic "Chunky" soup and Egg Noodles.
I would buy 10 lbs of egg noodles, and a case of this generic "Chunky" soup.
Directions:
Boil 3/4 pound of noodles, 5-7 min, Drain.
In the same pot, pour in one can of soup. Heat for 1 minute. Add noodles. Stir.
Eat bfast/lunch/dinner.
Cost per meal, $0.33-$0.50
You can add in anything that was in the fridge, left-over veggies, etc.
-SF