Beans, rice, and oats are very inexpensive foods and you can make many  different meals with them like chili, bean soups, rice stir-fries, burritos, and oatmeal.  Look at weekly sale flyers at your grocer or shop at your farmer’s market. Buy fruits and vegetables in season or even better grow your own if you can.  Container gardens are a great way to grow herbs and greens.  Growing sprouts is another great way to grow nutrient dense micro greens.