I grew up relatively poor, however my parents still made sure we didn't eat pure junk food out of frozen food boxes. We ate potatoes, lentils, beans, rice, pasta, lot of cheap veggies like cabbage. Parents grew some stuff too since we had a small garden, and I try to keep up that tradition in my back yard even though I'm much much better off income wise now. Families don't have to eat junk food, there's still plenty bulk stuff around. Not super cheap but at least as cheap as the processed garbage if you buy the raw ingredients.