AnkerDirect via Amazon offers its Anker PowerPort+ Quick-Charge 2.0 18-watt Wall Charger, model no. A2132111, for $9.99. Coupon code "7KPXZH3Y" cuts it to $6.99. Plus, Prime members bag free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $5.99.) That's $13 off list and the lowest total price we could find. This wall charger purports to provide up to eight hours of battery life from 15 minutes of charging.