Do I have to pay for the rental of an instrument as part of an extracurricular activity?

The equipment needed to participate in band at school would be considered an extracurricular activity.  Whether you would have to pay half of that cost would be determined by the wording in your court order.  If order requires that the parents agree on the activity, then the court would look to whether the parents agreed.  Is the cost reasonable considering the income of the parties?  Is the extracurricular activity reasonable considering the desires of the child, child's grades, cost, time committment, etc.? As a general rule, if the order requires that you pay half of extracurricular activities, then the instrument (whether it came from a school or music store), you would be required to pay half of that cost.