To be honest. If you don't have a contact to get perspex or acrylic for very cheap your best option would be glass. You can build glass enclosures for next to nothing at the cost which Builders are selling glass for.
Sure, it's nice to use perspex or some of those fancy, very light weight materials, but when it comes to money saving, and like the guys that has 100+ Tarantulas, glass would be the best cost-wise.
"God said it, we believe it, that settles it!!!"
This is why we should never take anything as the final result and set fact, but always be open to possibilities...this is where the adventure of discovery and connection between reality and the fantasy world lie.~ "Henry Howard Jnr"...