All4Cellular offers the LifeProof Headset Adapter for Apple iPhone 4 / 4S in Black (pictured) or Grey for $12.95. Coupon code "a4c10" cuts it to $11.65. With free shipping, that's the lowest total price we could find by $2. It's compatible with the LifeProof waterproof case for iPhone 4 / 4S and all 3.5mm headphones. Coupon expires November 19.