I've heard rumor that the mat is actually made from the same material that comes in rolls at your local grocery or department store and sells as self paper, albeit, as a foam like material.
I've also read that this stuff leaves a residue on your albums, however, it is unclear on whether it does and damage. It might be worth trying some of this bulk stuff out and see how well it works. At $2.00 a roll you could make at least 2 or 3 different mats