In order to be reimbursed for any purchase, you must first be pre-approved by the MTA Business Manager.
Assuming that the Business Manager gives you go-ahead, getting reimbursed is easy! See below for the expense reimbursement form. Just fill it out, attach your receipt(s), and put the form in the MTA box in the Theatre and Dance Offices. In about two weeks, the cashier in the basement of Haas will have a check ready for you! The cashier usually e-mails to let you know that your check is ready.