The real way to do this is buy a bunch of rice and beans and just eat it normally. You'll have cheap healthy food and be able to manage minor natural disasters. In more severe scenarios you have enough food to act as a stopgap for larger groups of people. You also naturally work through your stores instead of opening a bucket of freeze dried slop that's supposed to last for 20 years but tastes like ass and you're not sure if it's supposed to taste like that.