ZQ Racing just emailed out a newsletter with this coupon in it, does not seem targeted as my and my workmate have both used it to claim a mat!
( Email confirmation for order with free shipping http://i.imgur.com/Wig6ogo.png )
ZQ Racing make amazing chairs aswell if you are on the market i personally have their top-tier one and love it.
Edit: Looks like the site handling the checkout cant take much load at all, They should have prepared before giving out free stuff. Seems if you try a few times you can still get it to work.
Edit v2: Free shipping no longer available, shipping is $8.99