In the search for inexpensive media, I found an item called "Nu Foam" made by Fairfield. It is an alternative to foam rubber for outdoor cushions. It is a compressed polyester fiber pad much like scrubbies. It comes in multiple thicknesses, in bulk rolls and prepackaged sizes. I purchased mine at JoAnn Fabrics. The one inch thick rolls (27in wide) are 11.99 a yard. Two inch by 27in. are 18.99 a yard. If you sign up for their sales flyer you get a 40% off one regular priced item in each flyer and occasionally, they will put in a 50% off coupon. I was fortunate to have a couple 50% coupons so I bought a couple yards of the 1". In figuring cubic inches it was much cheaper than scrubbies at the dollar store!