Audioquest has marketed a relatively expensive Sorbothane TT mat (like $90?) that some people swear by and many others criticize. There are some 12" squares on eBay now for $8 + shipping. If anyone wanted to DIY a TT mat, he could buy a sheet, cut the circle and drill the hole for the spindle. At that price, the mat could be cut into pieces for damping other gear if the drawbacks outweighed the benefits.
Places like McMaster-Carr sell Sorbo sheets, but their prices are quite a bit higher.
