Your going to get what you pay for. If you want cheap, good service and quality parts then try here
http://www.newegg.com
others will reccommend several others. Also check out
www.pricewatch.com but be weary of alot of the sites. Please check with
www.resellerratings.com before purchaing anything. If you dont you may regret it.
Remember if the price is too good to be true it probably isnt a good place to buy. Many companies will offer great prices with horrible shipping and handling charges and when the prices are combined with the cost of the product you could have done better someplace else.