You can get discount foam if you buy a tractor-trailer load of it. It seems to go for about half price that way. Foam type, thickness, and quality varies, but is stated ahead of time. If you can get several households together it might pay. Not free, but...
Dan
Forget this weirdo. You guys wanna see something really neat? I just have to take off my shoe .... (hint: it's a tiny ad)
It's a bit like "run away to the circus" but for gardeners