Oxa USA via Amazon offers the Oxa Juice Box S2 10,000mAh External Battery Pack for $14.99. Coupon code "JCPBMNOT" drops it to $9.99. Plus, Prime members receive free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $6.48.) That's $11 under our mention of a similar battery from almost a year ago, $89 off, and the lowest total price we could find. It features an LCD screen, flashlight, and two USB ports.