Meritline offers the OnCore Portable USB Backup Battery / Charger, model no. ETC-500, for $12.99. Coupon code "MLC814YN" cuts it to $8.45. With free shipping, it's a buck under our July mention and the lowest total price we could find by $4. This battery / charger allows you to charge your phone from an outlet or from its built-in 1,300mAh back-up battery. It comes with six connectors and works with many iPhone and Android phone models.