Powerextra via Amazon offers the Powerextra 45-in-1 Accessory Kit for the GoPro Hero 4, 3, and 2 for $49.99. Coupon code "KMGTVD3M" cuts it to $37.99. With free shipping, that's the lowest total price we could find by $12. Accessories include a head strap, chest strap, monopod/tripod adapter, and floating handle grip.