I called my local plastics supplier and they quoted me $139 for a sheet but she stated they have a recycled material similar and is mainly used in marine applications. The product is roughly half the price ($65 for a 4'x8' sheet) and looks almost identical. Its called King Starboard, anyone ever heard about it?

I just got some more info on it, I guess HDPE so not the same as Starboard, not sure of any chemical characteristics...I will keep looking into it