In "Sam's Space", Aug. issue of Stereophile, Tellig reviews a new mat called "None-Felt" (no, that's not my misspelling--that's what the company calls it).
Anyhoo, it sells for about $30, but the same material can be obtained, probably in your hometown, for a small fraction
of their price, and you'll have enough material to make several mats. All you need is a pair of scissors. Plus, you can get it in black, blue, white, and green.
Contact me off-Forum and I'll give you the details if you're interested.