Don't the Israelis field a suppressed .22 for disrupting demonstrations or whatever? I definitely remember reading about that.
Yes, they tried to use suppressed Ruger 10/22s as less-lethal crowd deterrent. They thought that using low powered .22 ammo would not do enough to kill. Didn't work, though. Still killed. I think one of the strategies they wanted to use was to shoot the knees of protest leaders.
For a fighting rifle, it's better to go with a decent inexpensive higher power rifle.
Good affordable options for the working man:
Mosin Nagant 91/30. Under $100 and affordable surplus ammunition. Russian pedigree, a piece of history. What's not to like?
SKS. Again, Communist hardware. $200, affordable ammunition, loads with stripper clips. Nice sight upgrades with the TechSIGHTS. Decently accurate.
WASR Romanian AK clone. $400. Decent rifle, good reliability. Quality control has improved in recent times. Affordable ammunition.
SIAGA rifle. Russian AK, sporterized. About as accurate as a general AK is going to get. Cheap. Affordable. Can be evilized without too much effort if you are so inclined. Good quality.
Notice the Russian/Combloc hardware? It ain't always pretty, nor the most accurate, but it darn well works and is affordable for the masses. And, it's available.
Marlin 336 levergun. High quality. Accurate. Ammunition of decent power and relative affordablity. 6+1 shots most models.
Remington 760/7600 pump action rifle. Look for this one on the used racks, too. Full power rifle cartridge, 4 rd magazines, pump reliabilty
Stevens and Mossberg bolt action rifles...affordable and accurate rifles.
See? There are lots of choices if you are limited in a budget from anywhere between $100 to $500. You should be able to find these rifles under $500, especially used.
I still think you should buy a good .22 no matter what your other plans are, simply because they are enjoyable and will help you develop your shooting skills. They are also valuable for small game, and the ammunition is cheap and takes up little space. But it is NOT suitable for combat unless you have no other choice or cannot use anything larger (say you have a debilitating back injury or similar)