If you're willing to cook from mainly fairly simple ingredients, you can do it without much coupon clipping. Lentils, beans, and potatoes are dirt cheap, eggs are pretty cheap (a two-egg omelette is about $0.25 of ingredients), and, depending on where you live, there's usually some variety of fruit or vegetable in season and very cheap. Bread is also nearly free if you bake it yourself from flour instead of buying it. It'll still take some effort to keep it at $1/day, but if you're willing to do $2/day, it's easy.