: Remember that the "flutes" (the ribs inside) run in one direction. If you are folding the plastic, you’ll want to score it with the grain of the flutes.
If you are doing a large project—like lining a basement or building a massive Guinea pig enclosure—buying in bulk online is the most cost-effective route. where to buy corrugated plastic cardboard
: The go-to for bulk shipping supplies. They sell corrugated plastic in packs (often 10 or 25 sheets). Their shipping is lightning-fast, though delivery costs for large sheets can be pricey. : Remember that the "flutes" (the ribs inside)