There are plenty of USB chargers on Amazon with good reviews. Are you looking for one with or without a usb cord? Most allow you to plug in any micro USB cable.

http://www.amazon.com/Motorola-Wall-Charger-Micro-Cable/dp/B005LFXBJG/ref=sr_1_5?ie=UTF8&qid=1392068179&sr=8-5&keywords=usb+charger

Is cheap one that I have 3 or 4 of.