Amazon (asavings, 99% positive) has a GoPro Grab Bag of Mounts Sale Priced for $16.00. Prime members get Free Shipping or bring your order total to $35+ otherwise.

Includes 1 flat surface base plate, 1 curved base plate, a thumb knob and stainless steel hardware, 1 quick release buckle, 1 pivot arm assembly, 1 quick-release vibration plug, 1 leash tether, and a vertical J mount for mounting your camera on a vertical wall surface like a car bumper, wall, back of helmet, or similar. Works with Motorsports HERO Wide, Motorsports HERO, Helmet HERO WIDE, Surf HERO, or Wide HERO cameras.

Need an extra battery? Amazon also has the  Wasabi Power Battery (2-Pack) and New Charger for $23.99. (Fits GoPro HD HERO3+, HERO3 and GoPro AHDBT-201, AHDBT-301)