There are basically three kinds of pastel papers:
1. traditional part rag papers...like Canson Mi-tientes and Fabriano ...less than $2 a sheet
2. pumice coated papers like Wallis, Art Spectrum, UArt, Pastelmat, Richeson, Sabretooth, Sennelier, Ampersand and others
3. Velour paper.
I only use sand- (or coated) papers and at sometime I have used every one of them. None are cheap, BUT some are reusable. We all have mediocre pastel paintings. I routinely wash mine off with gamsol and an old bristle brush. This leaves me with a "toned" sheet of perfectly good flat paper. Read what Dakota Art Pastels has to say here. You may choke on paying $24 for a 2' x 3' piece of paper, but maybe you can share with classmates/friends...and trust me, paper is not the place to stint. It goes on sale, then I stock up. Get a pack. Put it in a safe, dry place and stop thinking of it as something you might ruin. Use it and re-use it. It is a beautiful tool. The invention of this paper changed pastel work from drawing to painting.
You can coat your own watercolor or printmaking papers...especially if you want to avoid actual painting (we all have those days) but I don't think the product will be as good and not much cheaper.
I have friends who use only velour paper and Cassatt and Degas only had Fabriano type papers. I sure am glad they used good quality paper and your great grandchildren may be glad you did,too.
I have no financial interest in this company, but they stock all things pastel and they know artists like sample packs. (scroll down) They also send out pastel sticks in assorted sample packs. And you can learn a great deal from reading their catalogue.