When I was in elementary school, we lived only 2 blocks from the school so I went home for lunch, in Jr High, I made my lunches because there were 6 of us kids and my parents didn't have the money for school lunches for us. In high school I had a job so I bought food from the little corner store across the street from the school that also had a small cafe where they made hamburgers which I think were around 50 cents. I either ate hamburgers or potato chips for lunch during my high school years, my idea of the perfect lunch
All the schools had hot lunches but I never ate a single one so I don't know what the prices were for them.