Brian, ask the people that have tax stamps for ASA's Econo-Can.
The suppressor I use on my Uzi cost me only $150 (plus stamp, etc).
I can see how $200 for a stamp doesn't seem so bad when compared to the price of a big ticket item. It does keep many people out of the game when they think "you mean I have to pay two hundred just because?"
Stopping power: The power some guns have to make you stop what you are doing and get your wallet out.