Woot offers (NEW) PowerA Joy-Con Comfort Grip for Nintendo Switch for $7.99 (orig. $14.99) + free shipping with Prime.

Product Description:
The Joy-Con Comfort Grip transforms the left and right Joy-Con into a single comfortable video game controller for Nintendo Switch. The ergonomic rubber grips keep your palms happy and your fingers from cramping during those long play sessions. Simply slide each Joy-Con Controller down the rails until they click, which allows the player indicator lights to shine through the center panel. Plus, the Comfort Grip stands up on its own, so you can display it next to your Nintendo Switch Dock.
 

• Lightweight, ergonomic design for comfortable gameplay anywhere
• Double-injected rubber grips for added comfort
• Easy slide-in design secures each Joy-Con
• Player indicator lights shine thru the center panel
• Game controller officially licensed by Nintendo