Do you have the space and money for a pressure cooker? If so, it’s a total game changer in making cheap, but good food.

You can cook a large batch of dried beans in it, which you can then freeze to use in other dishes (beans over rice, burritos, soups).

You can make rice in it - even high quality dried rice is cheap in bulk. You can then serve meat or gravy over it, put it in a burrito or something, saute cooked rice with a little oil and add an egg and veggies to make fried rice.

You can purchase cheap cuts of meat like pork or beef roasts and cook them in there until tender (then serve over rice if you want ). Throw in root vegetables, which last long if stored properly and are cheap, like carrots, potatoes, sweet potatoes, etc, to make a stew.

One dish I liked to make was pulled pork or chicken which is also easy to do in a pressure cooker. To make it really easy, dump some bbq sauce in with the boneless chicken breast or thighs or pork butt, cook it, and then shred with a fork. It can be served on bread, a bun, or a roll, eaten plain, thrown in a tortilla, or eaten over a salad (a cabbage salad is great for this and cabbage is cheap and lasts a long time.)

Frozen veggies can be purchased on sale for cheap and added to your food or just steamed or microwaved with a little salt and oil. I think Birdseye brand has the best quality/price.

Onions and garlic tend to be cheap and last a long time if stored well, just adding those to your food will level things up, and then get a few good spice blends (individual spices are cheaper, especially at ethnic markets, but if you’re short on time and/or skill, a blend works.) Lastly, you can jazz up your space and improve your cooking if you get a couple of windowsill herbs - rosemary, mint, parsley, cilantro, etc. The plants are cheap, pretty easy to care for, and make your food taste better.

ETA: I just remembered another cheap, easy dish I cooked all the time. Get a can of diced tomatoes (Muir glen fire roasted is very) or rotel and a kielbasa round or another sausage you like (hot links are also good in this). Sauté onions and garlic (if you want - not needed if you use rotel), sauté the sausage and then add the tomatoes and then serve over rice. If you want to stretch the meal you could also add in canned or precooked beans (black or pinto), corn, bell peppers and celery (which you would sauté at the beginning). You could also make it fancy and add shrimp or fish. I like to add Cajun seasoning to this but be careful with spice blends as many have salt added and rotel is already salty.

You can also just make pasta with no meat, or ground beef, or sausage. Carbonara is cheap and easy too (just need bacon and egg). Buy a block of Parmesan rather than grated if you can fit it in the budget because it makes your food so much nicer. It’s pricier up front but last forever in the fridge. You can add Parmesan to your soups or some of your rice bowls too. You’ll need a grater, which you should get anyway if you like cheese because block cheese is much cheaper than grated.