Patozon via Amazon offers the Mpow 36-watt 5-Port Portable USB Charger in Black for $21.45. Coupon code "MPOW36WG" cuts it to $14.45. Shipping adds $2.54. That's the lowest total price we could find by $5. It features three 5-volt 1-amp charging ports, two super charging 2.1-amp ports, and over-heating protection.