Just be aware that you will get what you pay for, the super super cheap ones are really mega slow and buggy. I've had pretty good luck with one of the lower priced (but not bottom of the barrel) ones; http://www.amazon.com/gp/product/B00B1ZNY38/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

I modified it a bit to make it more ascetically pleasing and to allow me to overclock it: https://imgur.com/a/rPunN