Oatmeal is the cheapest and most filling cereal around. Buy the quick cooking kind. Prepare in the microwave and top with bananas, raisins and maple syrup. On weekends make a big batch of pancakes and freeze leftovers. On rushed mornings microwave a short stack.
Burritos are easy to make.
Buy tortillas, add beans, salsa, and rice. Quick-cooking brown rice is ready in less than 10 minutes. Stuffed baked potatoes. Or try some chili. Peanut butter and banana sandwiches.