Instant oats

It's a cheap option, the only ingredient is oatmeal. I like to buy whole or half oats, so I have the option of making oatmeal flour when I need to. I use it in recipes, I like to make oatmeal porridge with banana and cinnamon.

One of the cheapest brand for oatmeals. Since most instant oatmeals taste the same, I usually just buy the cheapest option.