Anji - Simply walk into any glass & window store, tell them you are looking for blims, canceled orders or mis-cut panels.
I purchased 3 panels of safety glass, a yard long each for $10 from a local glass company.
Here is one I made from it, took $30 and 3 hours to complete total. I had home depot pre-cut the wood, assembly was quick.
dollar store bulb, box for a hide, old Tupperware bowl for water, and this snake was in heaven compared to where he was before.
Wayne