I've got that thingy - round with a handle - mat smoother - works OK on small shallow cuts & nicks - but not on deep ruts or missing chunks.
I know those large mats are about $50 or more - and I also need one - so either getting it on line somewhere - or Joann's with 50% off sale or coupon. Might need to checkout prices at Mill End too - sometimes they have really good prices on misc. items.