When I taught middle school, we made display boards out of foam boards. That saved us so much time and it was so easy to transport! You can just use packaging tape as "hinges" and tape 2 boards together. We also were able to stack the boards on top of each other for displaying with drywall brackets. Using these foams boards allowed us to assemble the boards ahead of time by stapling the work to the board and folding it. You could even have the students put the artwork on the boards right in class.