Depending on the program your child is enrolled in, there may be a recital/final performance at the end of the session.
Form My Musical Theater classes there are possible costs such as costumes, stage prep, venue or other. This all depends on how elaborate the group of parents of the children would like to make the performance.
In the past, some have kept the performance very simple and children have created their own costumes – other more sophisticated performances have included costume purchase or rental, stage, back drops, props, etc, and selling tickets to cover the costs to friends and family of the performers. It is up to your class/location to discuss with the teacher and determine what you would like to do.