i bought a set of infinity subs from sounddomain.com, and they threw in a free can. i think their regular price is 24.95$ but you can find lots of items that come with a free can, if youre shopping for other stuff anyway

it can be a bit messy, but if you prepair your area, throw down some cloths over your interior, it really gets into the little parts of your car which is nice. 1 can covered 2 doors, and my liscence plates (which were rattling like angry snakes before)

overall good stuff. next time i start a system, i know what my FIRST step will be, sound deadening