Retails for $13. The official pin number for this may be 119140.
Boba Fett can be hidden or "slide up" to be seen. He's held in place with a magnet.
From the Disney Store:
Classic Star Wars villains have been reimagined as rather less menacing "Tsum Tsum" characters on this pin. With its slider feature, you'll find Boba Fett lurking behind Jabba the Hutt, Darth Vader, and a stormtrooper.
* Created especially for Walt Disney World Resort and Disneyland Resort
* Enameled cloisonne
* "Tsum Tsum" characters include Darth Vader, Jabba the Hutt, Stormtrooper, and Boba Fett
* Slider function
* Boba Fett can slide up and down behind the other characters
* Goldtone finish
* Mickey icon pinbacks
* Part of our Star Wars Pin Collection
* 1 1/2" H (2" H with slider extended) x 1 3/8" W