I went to the fabric store with the wife to get some stuff for her , AND WALA all there foam sheets are 50% off . So I ended up getting 3 sheets of 3" x 24" x 10' long at a real savings . There sale ends tomorow so here is a link to there wb site . if any one else is doing this project over the winter .
http://www.joann.com/search?q=foam