But in all seriousness dishes that revolve around beans as their primary ingredient are good. I've bean eating tomato and borlotti bean soup a lot over the past couple of weeks with slight variations to it every time I cook it, either due to not having certain ingredients or wondering how other ones would mix well in the dish.
1 onion, diced (not 100% necessary but nice to have)
2 sticks of celery, diced (again, not 100% necessary)
1 carrot, diced (I don't bother peeling them)
2 cloves of garlic
1 400g can of tomatoes
1 400g can of borlotti beans (I've used other types of beans before, it's not a big deal what you use)
1L (4cups) of stock (I usually use chicken)
And a bunch of pepper and some salt at the end.
I usually double those ingredients since I like to make enough so that I end up just eating that for 2 meals a day, I also usually end up tripling the onions and carrots since I like both in soups and stews. Other stuff I add into the soup is turnips, parsnips, potato, cabbage, zucchini, swedes and diced bacon. For seasoning I add some bay leaves and have also added a tablespoon of Italian herbs into it. I haven't tried adding barley or anything like that into the soup but I've found that the soup ends up being pretty filling and nutritious, also depends on what produce is cheap in your area and what you can get on sale. Canned tomatoes and beans in my town tend to be around $0.80-$1 each, vegetables fluctuate but usually if you go to the markets or something like that then you should get a good deal. This is one of my main meals I'm using to help me lose weight. Dish goes well in a slow cooker as well.
Another cheap meal I make in the slow cooker is chicken and corn soup. Buy the cheapest cuts of chicken (usually chicken legs, ideally anything with bones for extra flavour), make sure to add stuff like soy sauce, garlic and oyster sauce for extra flavour as well.