Lightweight pvc is pretty commonly available... I think it's called schedule 20. And yes, it's easy enough to cut with either a hacksaw or a special cammed pipe cutter that looks like pruners with a big notch in one blade. Most places will cut it for you. My "mini hoop house" is made by pounding 18" rebar into the ground, leaving about 12", then slipping 3/4" white pvc from one rebar to the next to make a hoop. I have a series of about 6 hoops about 3 ft apart. To keep rainwater from taking the plastic down, I took an additional length of pvc and laid it along the crest of the hoops (hoop to hoop) to make a ridgepole, and then secured that to the hoops with good ol' duct-tape in an X lashing. It's survived 4 years now. Kay