I also think it depends a lot on who's there. If there are a bunch of supply vendors at the same show, then it often becomes a very competitive environment for pricing, and some really good deals can be had. If 99% of folks are just selling animals and the supply vendors are in short supply, you can bet prices will be at a premium. As an example, I was able to pick up a high quality 17" x 11" UTH at the last show I went to for $15 - lotsa supply vendors on hand, and prices were VERY competitive.
In short, if you're patient, you'll find what you need at the price you want to pay. Good luck!
RR_20 (Mike)