Don't do this, you'll be malnourished. Grains aren't a particularly good food group.
Potatoes don't require much prep, are generally cheap and filling, and will be much better nutrient wise. I'd still recommend rice and beans though. Canned beans work if you have no means to cook.
that's probably why most recipes ask to wash rice before boiling... im certain this works great... if your house's water-pipes were not made of lead hahaha.....haha.... sigh ._.
Potatoes are also really easy to grow. If you ever forget about your potatoes and they sprout or you leave them in the sun and they get green, you can put them in a pot and grow fresh potatoes.
Anyway poor people don't buy Kellogg's, it's overpriced. Poor people buy the generic cereals that come in those huge plastic ziplock resealable bags. Not only do they cost less but they have more intelligent useful packaging and the quality is fine too.