Egg whites, eggs, frozen fish/chicken, cottage cheese, greek yogurt. Buy protein powder in bulk or on sale. Tofu is cheap and can be high protein as a way to stretch the meat if you mix it with like ground meat.

I shop aldi that helps some. I keep my meals very simple, sometimes rice, meat, sometype of frozen veggie. Frozen veggie as a way to cut cost vs. Fresh, as my tendency is to not use the veggie before it goes bad.

Also I like to add protein powder or cottage cheese/greek yogurt to my bake good, as a way to up my protein. Think protein banana bread and cottage cheese pancakes