green HDPE board 1/8 inch price-Cus-to-size HDPE sheets . Feb 01, 2008 · HDPE is the cheapest machinable plastic you can buy. One inch HDPE is 250 bucks for a 48"x96" sheet. The price is pretty much by the cubic inch so you can extrapolate any size up to six inches thick. So far this year I have bought thirty sheets of one inch HDPE.