As a cheap-ass student I survived on soup. A can of soup is a bit over a dollar for the kinds that have stuff (veggies, pasta and meat) in them, you can heat it up on a stove and have a "meal" ready in a few minutes.

I wouldn't have qualms about doing it again. It was probably more expensive than buying fresh, but the time investment was low, it tasted way better than any frozen dinner, and it was way cheaper than doing any takeout.