They are probably about twice the cost of regular 22 ammo and come in a 100 piece pack. They should be easy to find if you have any decent gun shops or even walmart around you.
But they DON'T MAKE THEM FOR THE .22LR?
They dont make them for long rifle but they do make them in longs and that it the same casing as long rifle with a smaller bullet.
The CB's are sub sonic rounds like remington has mentioned. Other brands make them as well.