What you need to do is find something in a different application that has the material you need. For a crappy example look at a camper store, maybe they have a large piece of plastic. Or better yet a plastic table, then cut the holes and put some 3 inch 45 deg joints sticking out.
Anything I grow is for personal consumption only. I never ever sell anything. I hate buying it, I hate people making money off me, when its so easy and safe to grow. It is a victimless crime because it never leaves my home.