AnkerDirect via Amazon has the Anker Nano 5,000mAh portable power bank for Iphone with a built-in MFi-certified Lightning connector (in white) (https://www.amazon.com/gp/product/B0BV66TQ3G/ref=ox_sc_act_title_2?tag=quackdeals-20) for just $15.99 (originally $25.99). Free shipping with Prime or on $35+ orders. This pocket-sized charger is perfect for emergencies and easily clips onto your keychain or bag. Clip the $2 coupon on the product page for additional savings.
(https://m.media-amazon.com/images/I/61B0rkHb5ML._AC_SL1500_.jpg)