Both calipers are, and will be, readily available, and relatively affordable, for the foreseeable future. The question you're really asking though is - AR or AK.... And the answer is that it really depends on what you want out of such a toy.
AK's (half-descent ones, anyway) are known for being bullet proof (no pun intended). You can drop them in the mud, leave them there for a week or two, run 'em over with your truck, pick them up again, and they'll go bang every time. They'll eat any cheap, corroded ammo you feed them, and you can hold them above your head and scream "Wolverines" after defeating a squad of invading Commies with your high school football buddies
But they are a bit crude and basic (admittedly by design), unsophisticated, and won't win any beauty contests anytime soon.
AR's on the other hand, are a bit more sophisticated. You can get one at any price point you want, made out of basic earthly metals, or uranium coated, non-stick unobtainium if you have the cash. And their modularity means you can make them anything you want - from a short, fast, urban combat, M4 clone, to a match grade, 1000yd, fly swatter. There is quite literally nothing you can't build an AR to do - and all off of the same lower receiver if you want. But they do require a little bit more maintenance. You can run'em dirty, but NOT dry. And all the options for buying or building one just boggle the mind. There are a thousand manufacturers out there, making a million different parts. Even if you're buying a complete gun, you can get easily overwhelmed with options and price points.
Me personally, I like the AR. Both are proven weapons, but I'm a tinkerer, and like the modularity of the AR. It's also one of the most common rifles in the US. So should SHTF, spare parts and .223/5.56 would be much easier to find. And, it's just a bad-ass platform that's more fun than legal in some blue states.
As for the High-Point carbine....
If you're looking at it over an AR or AK, buy the Ar or AK. That said, it's a decent, pistol caliber carbine - especially for the price. I don't personally own one, but my father has one in .40, and a friend has on in 9mm. They are blocky, overbuilt, have poor fit and finish, and just plain ugly. But they work. I've seen very little complaints on functionality, and the two I've a chance to shoot, repeatedly, have shot flawlessly, and surprisingly accurate. If you decide to buy one, I'd go 9mm just for the price of ammo alone.
Good luck with your choice...
