'Puckboard', Regular polycarbonate from home depot, or PVC will work just fine for back yard stuff.
If you're trying to drop stacks and do it how a lot of mountains do it what you're talking about is UHMWP (Ultra High Molecular Weight Polyethylene).  About $650 for a 4'x10' sheet in 1/2" thickness.
Also.. Build a jib cult.