Sometimes, you have to look in interesting sources to find new things to help you, and then adapt them. For instance, I have a copy of a cookbook of Pennsylvania Dutch cooking, around 60 years old. It has a lot of good farm-style recipes, including things which you may find hard to get recipes for anymore. There are great soup and bread recipes, in particular.
But it also reminds me of how much some things have changed. The very first recipe under "Poor Man's Soups" is one that calls for 4 cups of milk and 2 eggs. And while it could still be made relatively cheaply, probably about $.75, I could make a more filling bean stew for less these days.
Of course, a poor man in farm country then would still have at least a little milk and eggs from his own farm animals, and the only other things needed for this soup are flour, salt, and pepper. The poor man soups are mostly these things, plus potatoes and onions. A couple of soups use broth instead of milk, and one includes tomatoes (specifying home-grown). Almost any farm would have these things available, and only the flour, salt, and pepper would have to be bought.
Bean soups and stews aren't included in the Poor Man's Soups, and I'm not entirely certain why. Dry beans were somewhat labor intensive in those days, but they were still considered a cheap, filling food. Oh, and there are virtually no pasta recipes in the book (a few with German style noodles), this was transplanted Northern European cooking.
Where I'm going with this is the idea that what was once cheap isn't always and vice versa, so it pays to look at all the recipes and if one sounds good, consider whether there are substitutions that could be made to make it cheaper. Some of the recipes under "Rich Soups" in this book would be a lot more modest now, for instance, and the amount of meat can usually be reduced. Some items in the book are much less practical now than they were in rural PA 60 years ago (imagine substituting beef roast for turkey...)
My cheapest, best tasting recipes often started by playing with this book. For instance, trying 3 or 4 recipes for potato soup, comparing them, then working out my own soup recipe. I used to make a holiday bread that people loved that I worked out after trying several recipes, but replacing most of the expensive ingredients with cheaper ones. Sometimes, the trick is knowing what can be substituted and what proportions aren't important on their own.
You probably can't find a copy of this particular cookbook; I've had this one so long I don't remember where I got it. But there are lots of other old cookbooks out there, and many of those may offer up gems of frugal, and delicious, cooking.