There are different strategies. One is to have cheap dry food plus some canned food in 5 gallon buckets. If you buy dry food like beans, rice, and pasta, you can get them from Walmart/Costco for about $1 a pound. This type of food will last a number of years, more if you put them in Mylar bags with oxygen absorbers. You need roughly 1 pound of food per person per day, and you can fit about 30 lbs of food in a 5 gallon bucket. For a family of four, you’ll need about 5 buckets for 30 days if you want to put in some canned food and things like spices etc so it’s palatable. A lot of people have some out of the way corner they can put 5 buckets.

Of course you’ll need a way to cook the dry food. The most sustainable way I know of is a small portable solar system and an instant pot. The instant pot is very energy efficient so you don’t need a very big solar system depending on where you live. If you store flour, you can also get a bread maker, which is pretty efficient.

The reason I like this strategy is that it’s cheap, and you don’t have to think about it very often. You can just trash the food after some number of years. You also don’t have to eat food close to its expiration date normally.

The only hiccup is fat. Cooking oil goes rancid, so you probably want to replace that every year or so, but canola/soybean oil is very cheap.

Of course none of this is very healthy, so you’ll want to include some vitamins…