The plan here is super simple. Give each of your students a stack of buddy passes for them to invite their friends to join them at a martial arts class! They can invite their friends from school, dance, soccer, their neighborhood, wherever! You can encourage them to pass them out by tying this in with a contest. Maybe each student gets an entry into a giveaway for a really awesome prize for every friend that they bring in with a buddy pass!
Your students do most of the work for you! Especially with school about to start back up, there is no reason for you to not be doing this.
We have buddy passes for every holiday and ideal marketing times of the year! If you don't see exactly what you need, just ask!