Soup. soup and soup.
I know how you feel, I’ve been on very tight budget most of my married life, after coming from a very rich family and it was hard to get used to.
green pea soup, lentil soup, vegtable soup with beans with whole wheat rolls are very filling.
I give my kids soup almost every day and it’s healthy full of vitamins! For the picky ones, add kneidlach or lokshon or a little sugar, soup nuts etc. . . .