iClever BoostCell Eco 15,000mAh Battery Pack | $20 | Amazon | Promo code PPPPCCCC

At first glance, this iClever battery pack looks like any bog standard USB battery, but if you look closely, you’ll also find a Lightning input port next to the standard microUSB port. That means that iPhone owners can recharge the battery pack without bringing a separate cable, and you can even plug in both inputs at once to recharge the battery twice as quickly.