If you want to stretch your food dollar, stay away from packaged stuff!
If you have a market where you can get whole foods, you're fortunate. If not, it's still economical even if you have to buy brand bags of beans and grain.
Cooking up a batch of quinoa, barley or wheatberries is a good start for healthy meals for the week, to which you can add a medley of roasted or sautéed vegetables like onions, carrots and zucchini, for example, and maybe a few black beans or kidney beans, topped with some chopped cilantro or basil.
Cumin and turmeric can really bump up the nutrition quotient!
For a side dish, tear up some romaine lettuce and sprinkle on some home-made vinegar & oil dressing with a sprinkle of Parmesan cheese, and you're set.
Instead of a grain, you can use pasta, along with some diced tomatoes for a variation on the first dish.
Preparing food that way costs very little per serving if you're "mixing and matching." The key is to make sure your vegetables out-number the other foods on your plate.
Grains and pastas are generally higher in carbs, and the key is to strike a balance by incorporating vegetables, which contribute lots of fiber.
Add a bag of apples to your pantry, and you've got a good start to saving money while you eat well!