I second the taco soup. I call it tortilla soup and do it a little differently, as they stated. It is really simple and really quite delicious.
I make it with a whole chicken which is fairly cheap, in a slow cooker, hard to mess up. But just the other night i made it with some plain chicken breasts i picked up that day. Butterfly cut them seared them off and finished them in the soup.
Three or four cups of Chicken stock.
I omit the taco seasoning and just use healthy amount of cumin and a little chili powder. Salt (depending on salt content of chicken stock), pepper, garlic powder.
Cans of corn, black beans, garbanzo beans, roasted tomato.
I recently started sauteeing a heap of mushrooms chopped to bits and adding that too.
Finish with a squirt of lime, some cheese, and tortilla chips, or i sometimes crisp up some regular corn tortillas and cut them up in it.
Super simple, tasty. I personally can eat it throughout the week.
Gazpacho. Throw whatever veggies you have in a blender, season and bam - soup. Add a filler if it doesn't keep you full. Beans, lentils, potatoes, rice are all good options.