I am serious! Put that change towards your next treatment.
I view massage as part of your health care plan. Just like you brush your teeth, strive to eat healthy, and find that work/like balance, massage is one of those tasks that helps life run smoothly. Why would I ask you to bring a routine of massage into your life, then ask you to pay me over my rate to provide it to you?
I would much prefer you keep that money you may think you owe me, grab a few business cards, leave a review on Google, and spread the word of massage as a part of your health care plan. The best "tip" I can receive is you sending someone my way who is ready to benefit from bodywork and massage.