Woot offers ZTECH Percussion Massage Gun for $52.99 (orig. $119.99). Free shipping for Prime Members.

Product Description:
Intended for pre-workout and post-workout, the ZTECH Massage Gun will improve your fitness regimen by warming up your muscles prior to exercise to avoid injury and after exercise for deep muscle recovery. 

• Includes 6 Interchangeable heads and carry case
• 6 Speeds
• Cordless
• Helps relieve muscle stiffness and improve blood circulation