Cost... Not much!
Someone had a part roll of 6 mil vapour barrier leftover from a home reno project. A roll of vapour barrier at the building supply stores probably runs about $30. We used a dozen 1.25 inch wood screws and a couple dozen 2 inch finish nails, and three 8 foot pieces of 1X3 strapping. One of the guys gave us a big spool of cotton string that we used for lashing. Oh, and the inevitable duct tape to pad the pointy bits of the sticks and seal up accidental punctures. The sticks were free, we cut them at a woodlot a friend owns.
All in I guess about $25 worth of materials if we had to buy it all. And you can portage like a hat.
Wood Hoarder, Blade Sharpener, and Occasional Tool User