Hunting
To eat or not to eat. That is the question!
Do you have scenarios you're planning for that involve needing to acquire/produce food over a long period of time? If so, you've probably got some component where theres a need have meat. That can happen in many different ways. If you've got a solid electrical plan, maybe stocking up on grocery meats is ok, maybe fishing is ok. What we want to talk about here is hunting to acquire meat. There are huge numbers of ways to hunt, probably the most popular contemporary way is with a gun of some sort, but thats not the only option. Bows, spears, knives, snares, traps, birds, dogs... tons of ways to make it happen. Here are some general thoughts:
Certainly hunting with a gun is an effective way to acquire meat. It might be a good idea to have a few different types in your plans. First, a shotgun. Very versatile, able to take down birds to bear and everything inbetween. I believe 12 guage will be the most common, and have the most common ammo available. Automatics can jam, for longer term I don't think you can beat a pump. Shotgun ammo today 2-1/2,2-3/4, 3, & 3-1/2. It might be best to find a shotgun that shoots all of those varieties, not because you want to but because it can probably shoot any 12 guage ammo you come across. I'd hate to be in a position where the only ammo i can find is 3-1/2 and my gun won't shoot it. On the other hand, in my experience, most ammo thats out there is 2-3/4 or 3" so having a 3" shotgun might fit better in your budget.
Next would be a .22LR or (LR=Long Rifle) rimfire. There are thousands of varieties of these out there, great for taking small game. Definitely a great one to have.
Last would be some larger caliber rifle for big game. Stick with a common caliber. This is always a sticky subject, everyone has their favorite caliber and rifle, but in a long term need scenario I'd rather have a rifle that has the most ammo available for it. Some very popular calibers that have had huge production runs would be .223, 5.62, .270, .308, 7.62, 30-06, and .375 H&H (good article here https://www.americanhunter.org/content/why-every-hunter-should-own-a-rifle-in-a-common-caliber/ ). The one that stands out to me is the .308 as generally 7.62 ammo will run in a .308 (not necessarily the other way around though so be careful). It's been around a long time, and its compatibility to fire a 7.62x51 NATO round gives it an edge by having a huge pool of ammo to draw from.
Having these three guns would cover most north american game. The only game it might be underpowered for would be a grizzly bear. If you live in an area with grizzlies, and you'd like to keep them on your food list, you might consider something with higher power.
So that kind of covers calibers of guns to keep. There's a ton more to consider when acquiring them such as: Feed Method, Magazine Capacity, Legality in your expected area, sights, finishes, cost, sling styles, and breakdown ability.
What if your gun breaks or you don't have ammo? How about other methods. Heres some other methods to think about learning how to do:
Snaring
Foot Traps
Bow/crossbow Hunting
Slingshot
Hunting with Dogs
Hunting with birds
Spear hunting
Explosives
Snaring is definitely one of the most recommended methods of acquring food I have encountered in my research. The most popular target for such? Rabbits. Seem like a good one to have in your bank of knowledge how to do, as all you need is a few sticks and some thin wire. Time and luck does the rest.
I feel guilty about writing this and not mentioning fishing, but thats a large enough topic that it deserves it's own page.