A supressor should cost no more than a decent flashlight and be sold almost everywhere you find the usual sporting goods.
I agree. Suppressors are basically a miniature car muffler. Granted, they are machined to fit a particular weapon and precision crafted, but they are not worth the outrageous prices of today.
One of the most popular weapons is the AR15, one would think mass producing a silencer for that weapon would bring the price down to less than a hundred bucks. They could be accessory items on the shelves of all sporting goods stores.