Bread is expensive? Anyway, living off whole foods is cheap as hell, other than meat and some more exotic fruits/vegetables. Use things oats, rice, lentils, etc for carbohydrates and the bulk of your calories, eggs and ground beef for protein and fat. That would be the absolute cheapest way to go, but I think even on $30 you could still probably afford things like chicken breasts, fish, olive oil, vegetables and fruit as well. Unprocessed food is cheap.