450 Watts would run that easy and allow for a bit of upgrades for the price of a quality 450 watt power supply you can spend a few more dollars and get a 550 Watt that would be good for about any future upgrades you could make.
Sorry I can't recommend a lower priced cheap PSU.
http://pcpartpicker.com/products/compare/xVkD4D,DPCwrH/