Sometimes it takes a little extra persuasion to encourage folks to give your business a try.
It's easy to offer a free trial through Punchpass. Just set up a "Free Trial" pass that costs $0.
You won't offer the trial pass online.
When a new customer calls for a reservation or comes to class, you can set up their customer profile -- and be sure to collect their email! Then you can just assign the trial pass to the new customer:
Once the pass has been assigned to the customer, you take attendance normally. The new customer can make reservations normally too.
When their pass runs out or expires, they will have to buy a pass. They'll get an automated notification when their pass is nearly up! :)