You may also want to check pricing with McMaster-Carr. They have a LOT of HD/UHMW polyethylene in their catalog (in a couple of different colors, even!) but it looks like the pricing isn't any better. At least you can order much smaller sizes.

: I wonder what the going rate is for the plastic for a Yost folding boat is
: these days. I live on the north end of the LA (Santa Clarita) I check at a
: plastic supply house and the told me it would be $300.00 for a 4 x 8
: sheet, had to buy the whole sheet. He was helpful, said he thought it
: would be about the same at a big box store. He also indicated there was a
: special formulation for exposure to water and salt water that he highly
: recommended, same price and more or less the same stuff.

: anyone got half a sheet to sell?
: Meanwhile I am slowly making progress on my S&G, would be faster if I would
: just go ahead and make the mistakes and then ask for help to fix it.
: Perfectionism really slows the build.
: thanks, John