We don't really do cereal, though I'll occasionally buy store-brand cheerios. They tend to have those for a snack rather than a meal though. My older son loves oatmeal, which I buy in big canisters. It's really really cheap that way. Cook it up, add some fruit, almond milk, brown sugar, maple syrup, honey, yogurt, or some combo of the above. A little sweetener goes a long way, and you control exactly how much they get. Plain yogurt, bought in big containers, with your own sweetener and fruit stirred in. I also make pancakes, with pumpkin puree, zucchini, and/or greek yogurt added. When I do that I make a huge batch and freeze a bunch. I also cook and freeze waffles. My other thing is to make a giant pan of frittata, with tons of vegetables (usually shredded zucchini or spinach, but any leftover veggies work).