White Bean Spinach soup.

Very simple.
White drry beans, tomatoes, spinach, onions, celery.
Seasonings. We make soup and freeze it and have it for a lunch along with a salad.
This is a large serving here. High in fiber and protein

White beans are high in starch, so this is not something you would want to eat a large amount of but its a low-cost soup. Something to eat along with a salad instead of meat.
Nice on a cool March day, still soup weather but nice enough to let the windows up in your home.

You could add a small amount of grated parmesan cheese. (small) or spicy red pepper flakes.

Something that does not cost alot

We make bean soup:lentils, dark beans, black beans. In this case split pea.
I take a can of no salt added tomato, chopped onions, celery, carrots. And about 2 cups of beans. And add spices such as onion powder, cumin, parsley. Any spices really.

The soup is very low fat and can be a nice meal along with a salad.