All4Cellular offers the OtterBox 1000 Waterproof Case in Black for $6.95. Coupon code "A4C6A5" cuts it to $6.60. With $2 for shipping, that's the lowest total price we could find by $2, outside of the price below. This floating case is waterproof (up to 100 feet) and impact-resistant. It measures 4.8" x 3.6" x 1.6" on the outside and 3.7" x 2.3" x 1" on the inside. Deal ends October 31.

A close price: Abe's of Maine has it for $10.34 with free shipping.