To follow up from Ed, it also depends on how willing you are to learn somewhat intricate and unusual techniques, and spend the time to deploy them, in the name of thrift.
Example: One whole tilapia or similar fish -- I said whole, like head and all. You can get those pretty cheap. That can be two easy meals, or three if you're very open-minded. If you fillet the fish yourself, you have three parts: 2 fillets and everything else. Each fillet can be broiled, seared, steamed, or whatever, and served with Yeti's rice. You can then split the head, shear the spine into fat chunks, and cook all those bits in soy, ginger, and dashi, and the result is another meal -- very popular and old-fashioned Japanese home cooking.
The problem is that you have to look for whole fish, you have to learn to butcher it whole, and you have to be open to eating a meal whose primary protein is fish head.
That's just one example, but it should clarify Ed's point, which is dead-on. What he can live on, what I can live on, and what you can live on are three different things.
Can I suggest that you pick up one of those general-purpose cookbooks aimed at beginners that you can get at any used bookstore? I mean things like Betty Crocker, Better Homes and Gardens, and so on. Joy of Cooking is better in many ways, but it is usually rather more expensive.
Whatever you're thinking about buying, look carefully at the index: you want to be able to look up that stuff sitting in the bottom drawer that really needs to be used ASAP, not just primary ingredients. So for example, if you have four carrots that you meant to use up and forgot about, you want to be able to look up "carrot" and not just get carrot dishes as such -- you want some indication of every dish that features carrots, at least in any significant quantity. That way you can look and go, "hmm, that sounds good, I already have the onions and a jar of olives, guess I just need a couple shrimp" and you're ready to go to the store.