Anker PowerCore 16000mAh + Astro Mini 3200mAh Charger $37 at Amazon

Amazon with Anker Direct has the Anker PowerCore 16000mAh 2-Port 4A Portable Charger for $37. Add to cart, then add the Anker 2nd Gen Astro Mini 3200mAh Lipstick-Sized Portable Charger to reach $57 - $20 off with coupon code 8WLFPMG7 at final checkout = $37 with free shipping. Features PowerIQ technology which purports to intelligently charge your devices faster than standard chargers.

Excellent Amazon reviews.