I use the white plastic ones from Hamilton. They let in enough light for my solar panels to keep my batteries fully charged. The trick with a cheap tarp is the framing. I take my stantions off and run a ridge pole so that the slope is about 55 degrees. I have had zero snow on the tarp this winter. Not bad for a cost of about $75 every other year. My frame consists of three 2x4 12's supported at the bow, stern and the two joints between the boards. No side supports other than a few lines run to stantion bases. This year it took about 45 minutes to set up the frame and cover the boat. Most of the time was tieing the tarp down