Amazon offers the LifeProof Nuud Waterproof Case for iPhone 6 in Avalanche White, model no. 77-51110, for $40 with free shipping. That's $17 under our September mention of another color and the lowest total price we could find for any color now by $4, excluding the below mentions and other Amazon vendors. It's purported to be fully submersible to 6.6 feet for up to one hour. This shock-proof case is also IP-68 rated for dirt and snow resistance.

Of note, Amazon also has it in blue or pink for $40.99 with free shipping, and Seller1ON1 via Amazon has it in black for the same price.