The cheapest among healthy recipes is lentil soup. 99c per package of green pees. Pour some water into pees, let it stay for 30 min to let bad stuff out. Then change for clean water and boil till ready. Salt, pepper. You can add onions and carrots and boil along, or cut and fry vegies, then add in the end. Also, you can add some sour cream plus parsley into your plate (not the whole pot) Delicious.
For breakfast nothing beats oatmeal, but it has to be "old-fashioned", which is your healthy choice. I cup of oats, 1 cup of milk (almond milk), 1 cup of water. A bit of sugar, raisins, maybe nuts. If you are allergic to milk products, you can cook oats in 2 cups of water (add a beef bullion cube for flavor) Also, when oats are ready, add parsley for fresh flavor!
For lunches, it's easy to make burritos. You can cook meet in advance. Fry ground beef with salt and pepper, let water/juice out. Take tortillas, spread some re-fried beans from a can (and/or sour cream), add meat, add salsa, cheese. Fry in olive oil, both sides till crispy. I prefer small soft flour tortillas. They end up looking like crispy tacos :) Very good Salsa is Garden Salsa from Costco.