Kmart offers the Activeon HD Action Waterproof Camcorder, model no. CCA10W, for $99.99 with free shipping. Plus, Shop Your Way Rewards members earn $51 in SYWR points. (Not a member? It's free to join.) Assuming you'll use the credit, that's the lowest total price we could find by $71. It features a 5-megapixel CMOS sensor, 2" LCD display, 6-element aspherical glass f/2.4 lens, 1920x1080 (1080p) recording at 30 fps, and waterproof housing.
Of note, Shop Your Way Rewards members may be eligible for additional credits and discounts.