1,900mAh Battery Case for Apple iPhone 4/4S for $15 + free shipping
All4Cellular via eBay offers this 1,900mAh Battery Case for Apple iPhone 4/4S in five colors for $14.99 with free shipping. That's within a buck of the lowest total price we could find for a comparable 1,900 mAh battery case elsewhere. It features an LED indicator and capacity test button.