eCase via Amazon offers the Kmashi 15,000mAh Dual-USB External Portable Battery Pack in Black/Red, model no. MP836, for $16.99. Coupon code "BY6YG3UB" cuts that to $12.50. Plus, Prime members bag free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $6.70.) That's tied with our February mention, $37 off list, and the lowest total price we could find. It features a 2-amp USB port, 1-amp USB port, status LED lights, and a microUSB cable.