As one of its daily deals, Amazon offers Prime members the PNY HD5000 5,000mAh PowerPack Universal Portable Battery Charger, model no. P-B-5000-12-K01-RB, for $19.99 with free shipping. (Non-members can spend $35 or more to dodge the $8.25 shipping fee.) That's the lowest total price we could find by $5. It features dual USB ports, power status display, and a micro USB cable, and provides up to three charges at full power. Deal ends today.