FREE hair glitter at Magic Kingdom can be found in several different locations. While we have not had the pleasure of experiencing this yet, I still suggest you seek it out on your next trip! You can visit Castle Couture or Sir Mickey's gift shops in Fantasyland. Find a cast member to sprinkle some "Pixie Dust" in your hair! I've also heard that if you can find a "Fairy Godmother in Training" at Bippidy Bobbidy Boutique you can get a free pixie dust sprinkling here too!
Several years ago (in the photo above) we were able to pay $5 to get colored hair gel and Mickey sprinkles from Harmony Barber Shop on Main Street USA by the Fire Station. However, I'm not certain they still offer that service.