Hi Ray. Fees vary widely from $0 to $800/conference. We have been vendors at approximately 200 conferences since we started our business in 2004.
There are 2 different categories of vendors/exhibitors.
The first is a vendor who wants to connect with the students and teachers. This would typically include jewelry and theatre branded attire/trinkets, publishers who carry scripts for student directed shows and competitions, and college/university recruiters.
The second type would be vendors who want to connect with the teachers, like publishers who carry readily recognizable pieces (MTI, TRW, Samuel French, Dramatic Publishing, etc), companies like ours who develop and carry instructional programs, supply houses that sell durable goods (lighting, audio, tape, paint, etc), travel companies who take students to NYC, London, LA, etc, textbook publishers, etc.
Many of the vendors do some of both, like Theatrefolk, who offer 1 act plays that are used in competition/student directed productions, and also offer full length, mainstage scripts.
Here are some things vendors look for:
1. Total attendance: be sure to let potential vendors know past figures, broken down into teachers and students
2. Location, exhibit hours and dates, If exhibits will be in a secure area (if more than 1 day), electricity fees (we had to pay $165/day at one major hotel, and the conference was 3 days), if there is a dedicated time for teachers to visit the exhibits, fees, lodging costs, etc.
3. Perhaps most importantly, for vendors looking to connect with the teachers, a "passport" system. The passport works like this. Each teacher gets a grid on a piece of paper with each vendor's name in the boxes. As the teachers visit each vendor, the vendor stamps or initials their box. Then there is a drawing for various prizes (furnished by the vendors who choose to participate). We give Shure mics, and Backstage Survival Kits (packs of spike tape and glow tape, blue LED flashlights, a classroom set of 1/8" lighting templates, grease pencils, etc.) Some publishers donate a royalty package for one of their shows. It's a way of getting the teachers to the exhibit area.
Also, check with your local city hall to see if the vendors need to buy a license to sell things. I some places, the vendors also need to collect state and local sales taxes, and do the necessary paperwork with the city and state to sell anything at a conference.
The more you can offer the vendors, the more likely they are to pay to exhibit. The conferences that charge the most offer the most to the vendors.
Hope this helps some!
Bob Fowler
Interactive Educational Video, LLC