Get this Urge Basics 2400mAh Battery Case for iPhone 5/5S for $29.99 plus free shipping at Staples.com. This was the lowest price we found by $7. It comes in three colors: black (pictured), silver/clear or silver/blue. It works both as a protective case and a battery backup that can double the battery life of the phone. Note: It does not interfere with the fingerprint reading function of the iPhone 5s. Sales tax is charged in most states.