He's probably talking about Dynamat Extreme which is a fair amount more expensive than the regular stuff. This website says that it MSRP is $250 for one box of 36 sq feet.

http://www.b-quiet.com/dynamat.html

So far that website is the only one I've seen that lists specific performance numbers for dynamat and the other sound-dampening treatements so that you can make a (more) educated decision.