I’m retired military. Never owned a personal weapon until five years ago. Stocking up on MREs, too.
I am a big fan of waltonfeed.com
$600 or so will get you a PALLET of food in 6 gal. buckets packaged to last at least 20 years. Get the stuff that is mylar bagged with oxygen absorbers for longest life. They sell organic grain, honey, etc. too.
The best and cheapest way to prep is to buy beans, rice, powdered milk, oats, barley, and other things that require only cooking. Add a quality pressure cooker and, later, a good grain mill to make flour, and you’re all set.
I don’t rotate the 20 year life food until it hits 20 years. I rotate the pantry foods.
A small closet can hold enough food to keep your family going for a year.
You need a pantry with canned goods, spices, etc. to complete the basic foods. I keep a supply of cooking oil in the spare fridge to prevent rancidity.