Feed corn! YOu can get 50 pounds for about $7. I eat a lot of mush. I make "polenta" and put all kinds of stuff with it. It is way cheaper than pasta and even cheaper than rice. Use it to vary your diet now and when you are totally dependent on your storage foods.
I never buy soups. They are expensive and I don't care for the taste of them. My DD cannot have them anyhow because of gluten problems.
Things that will add body/flavor to soups are powdered onions, browned flour (or cornmeal or rice), dried nettles, leftover coffee, kelp granules (taste a bit fishy), tomato powder,other powdered dried veggies.
If you use soy, buy the beans and learn to make your own soy milk and tofu. The leftover fiberous bean bits can be dried in the oven and added to meatloaf or other ground meat dishes. To avoid a beany flavor bring the water to a boil and pour in the dried soybeans. This kills the enzyme that causes the beany taste. The enzyme also has antinutritive factors that are deactivated by the boiling.