I have no stake in this but I thought I would share. They quoted me $29.00 plus shipping for a .5"x4"x48" piece. It seems like a really good price - UHMW Sheet | UHMW Sheets | Plastics International.
UHMW, also known as ultra high molecular weight polyethylene (UHMW-PE) is a high performance polyethylene with a much higher molecular weight than standard polyethylene. This substantially higher molecular weight accounts for the increased wear resistance, chemical inertness and low coefficient of friction. Typical applications includes wear strips, wear profiles and any other applications that require abrasion resistance.