well....there are many sites that i buy online from. One very reputabale site is www.newegg.com most of the time their the cheapest and not to mention the have the best rma service and best shipping also!!!!

now if your want to find the part for the cheapest here are 2 sites that can price it for you

www.pricewatch.com
www.pricegrabber.com

and there 2 other sites that post deals that can be found

www.slickdeals.net
www.fatwallet.com

ive bought with newegg for years...build 4 computers using their service!