I was about ready to drop $400 to treat my edit suite with 96' of Auralex, then I did some more shopping and found this...
http://www.cameronpackaging.com/egg_crate_foam.html
I am NOT doing anything super critical...I just need to deaden a room a bit (it's 14'x 14', four walls, 8' ceiling and hardwood floor). So, first I'm wondering why this stuff wouldn't be as good as Auralex. Second, why is Auralex so expensive?
This might be in the middle. I found a place where I could buy a box of 24 2" pyramid foam 1' squares for $30, including shipping. I'm going to find some chicken wire and build a cylinder enclosure for my new shotgun (got a noisy room).
http://www.foambymail.com/Pyramid.html
By the way, I also bought a box of the auralex mineral foam, intending to use it to help block two windows, but it's relatively stiff, and rigid where I was thinking it would be soft and squishy. Instead, I'm going to cover them with fabric (six 2 x 4' panels, 2" thick) and hang them as wall absorbers.