Amazon offers the mophie juice pack iPhone 6/s Plus battery case for as low as $57.62 with free shipping. Aside from Best Buy that has the next best pricing at $74, nearly every other retailer is selling these cases for between $80-$100. Discounted colors include Black, Gold, White and Rose Gold with prices topping out at $62. The additional 2,600mAh of battery can extend your iPhone’s battery life by more than 60%, which is an absolute lifesaver for when you’re on-the-go. More than 730 Amazon reviewers rate it 3.7 out of 5 stars.