The first 3 are actually illegal in the US unless they were made before1986, and even then they require a special license per firearm that takes a year to get. And those pre-1986 guns start around 40 grand.
You can get modern guns that look like an AK, M16, or Uzi, but they have to be manufactured in a way that they can’t fire full-auto without illegal modification. For instance, I can take a full-auto trigger and drop it into my AR-15 and it still won’t fire full-auto because the lower receiver (legally the gun) is missing a hole required for the auto-sear that allows the full-auto to function.
Desert Eagle is a sub-brand of a company called Magnum Research and is a family of firearms. Most famous among them is a variant that fires a 50 cal Action Express round, but you can get it in a 357 or a 9mm as well. Saying “Desert Eagle” is like saying “Xbox.” I probably know what you mean, but it technically covers a lot of devices.
The Awp is a very specific model of Accuracy International precision rifle. They’re quality precision rifles, but they’re also like 15 grand, and for 99.999% of shooters you could spend $3,000 on a Ruger and a decent optic and shoot just as well. I have a Bergara custom rifle and a top-of-the-line Razor optic that are combined worth about 7 grand (mostly the scope), and I honestly don’t think there’s a human on the planet who could shoot well enough to determine a meaningful difference between it and an Accuracy International.
“Magnum” essentially refers to a larger, overloaded cartridge. They’re usually just a little longer so they can hold extra powder. My 44 magnum revolver will shoot 44 special (regular) or 44 Magnum. The projectile is the same, but you’ve got like double the bang with a Magnum.
Honestly, for handguns there’s no reason outside of bear defense to use a Magnum other than for the giggle factor from the big boom. My 357 Magnum also fores 38 special which, while technically weaker, can be fired more quickly with greater control in a tighter group at revolver distances, and a 38 special will take down just about anything. It’s the difference between killing a fly with a fly swatter or a sledgehammer - the sledge is more powerful, but I wouldn’t say it’s the better tool.
Handgun refers to any firearm designed to be fireable using 1 hand and no shoulder stock. A pistol is a handgun in which the firing chamber is integrated into the barrel, inclusing most single-shot, automatic, and multi-barrel handguns. Revolvers have a rotating cylinder with multiple firing chambers that line up up with the barrel before firing.