Cafago offers this 4K Ultra HD 30fps WiFi Action Sports Camera in several colors (Yellow pictured) for $31.95. Coupon code "ZD4640MG" drops it to $27.99. With free shipping, that's $2 under our mention from three weeks ago of a similar model, $24 off list, and the lowest price we could find. Features include a 2" LCD, up to 4K video recording at 30fps, 16-megapixel CMOS sensor, 170° wide-angle lens, WiFi, microSD card slot, and housing that's waterproof up to 131 feet. It comes with multiple mounting options.
Note: This item ships from mainland China and may take two to six weeks to arrive.