Cheap nutritious foods I eat often:
Oatmeal almost every breakfast (optional raisins, fruit, cocoa, brown sugar, a few walnuts, ground flax seed, soaked chia seeds, cooked maca powder, ceylon cinammon, etc.)
Pancakes (whole wheat flour, baking powder, baking soda, brown sugar, water, no eggs required. Fried with butter very small amount of butter. Optional almond flour, buckwheat flour, etc, oatmeal, raisins, Raw honey instead of syrup, ...)
Soup. (Dried bean soup mix + barley flavored with spices or canned soup once in a while)
Whole grain bread with butter, peanut butter, raw honey, etc.
Quinoa with spaghetti sauce, cheese sauce, soup, etc.)
Coleslaw with lemon juice, extra virgin olive oil, with optional onions, spices, raisins, etc.
I've tried frozen and raw vegetables for many years which is ideal, they don't keep well so I buy canned vegetables now
Popcorn popped on low heat with olive oil. Butter and nutritional yeast topping.
Raw potatoes are cheap. Good with butter, onions, spices, mushroom soup, canned tuna, vegetables, sour cream, cheese, etc.
Sandwiches.
I avoid anything that has vegetable oils in it but I'm not extreme about this. Causes chronic disease. Research Omega 6 health hazards of vegetable oil.
I also avoid foods with salt, sugar, and especially high fructose corn syrup. I no longer have a salt shaker but foods I buy might have a small amount of "bad" stuff.
For the last month I've been doing "intermittent fasting" because research shows it great improves health and longevity no matter what you eat (within reason). This has also saved a lot of money on food and I feel better. Now that I'm used to the routine, I'm rarely hungry.
Hope this helps. I'm wishing all of you good health.