Collect contributions from students in class or contact other parents with students in the class.
Most day spas offer a variety of services at many different price ranges.
Purchase the gift certificate. If you have money left over, consider buying a some bath salts or a card to present with the gift certificate. If you purchase a card, don't forget to let each person who contributed sign their name with a brief message to the teacher. A full-body massage is something that most teachers would love to have, but would never do for themselves. You pay only shipping and handling.