Eggs offer flavour and texture to various meals and desserts. One big egg has 6.5 g of protein, and a dozen costs $1.55.
Peanut butter is delicious on toast and in sauces and desserts. Natural peanut butter has 7 g of protein per 2 tablespoons and costs roughly $1 per 100 g.
Yogurt can be consumed with granola or fruit. It's used in smoothies, sweets, marinades, and sauces. Yogurt has 5.3% protein per 100 g. Average cost is $0.50.
Bulk soy is cheap. Roasted, they can be eaten alone or in salads. Homemade soy milk is possible. Soybeans cost $0.94 per 100 g and provide 16.6 g of protein.
Legumes are an inexpensive meat replacement. Bags of dried legumes cost a few dollars and come in so many varieties it's hard to give a single price.
Protein powder is often called whey. Smoothies, sweets, and energy snacks. Protein powder costs $2.30 per 100 g if you browse around.
Seitan, cooked wheat flour, replaces meat and fish. 25 g per 100 g of protein. $1.57 per 100 g for prepared seitan. Cheaper is homemade seitan.
Don't toss squash seeds! Protein-rich. The seeds of a butternut squash provide 11.87 g of protein per cup. Roasted and salted, they're great on salads.
Served chilled with a sauce and veggies, quinoa can substitute rice in any recipe. 100g cooked quinoa has 4.4g protein. You can get the same quantity for $0.55.
This hard-to-find grain is worth the effort. Amaranth has 5 g of protein per half cup, like quinoa. $0.63 for 100 g of amaranth.
Buckwheat goes nicely in salads or handmade bread, like amaranth and quinoa. This grain has 13.3 g of protein per 100 g for $0.71.