Make a big pot of "soup" within anything you can scrape together. Serve with bread day one. Day 2 thicken it, spice it and serve with rice or pasta or whatever you have and serve as curry. Day 3 stick it between pasta sheets and a bit of white sauce and serve as lasagne.
I have a very very small budget and apart from sourcing reduced food I make large amounts of what I call "basics" that can be frozen in portions to suit your family size, defrosted and embellished as above.