I'm a fan of steel-cut oatmeal, which is more of a production. But my kids will eat regular oatmeal. Couldn't be easier or healthier. For each serving: Combine 1/3 cut old-fashioned oats with 2/3 cup nonfat milk in a Pyrex bowl. Microwave on high for about 5 minutes. Stir and add more milk as necessary for texture and temperature. Serve with frozen blueberries or dried fruit, cinnamon, and maple syrup. Now that's fast food!
I also 'make' a pot of unadulterated oatmeal while I clean up the kitchen after dinner (e.g. - pour water and oatmeal into a pot and leave to simmer). Toss in add-ins in the morning and microwave.
I just bought organic rolled oats in bulk for $1.09 a pound. Along with a sliced banana and a little soy milk, a serving still costs a fraction of what McDonald's charges.