Where to get the cheapest computer parts

The store arent always the cheapest…sure you might get the occasional deal here and there but if you wan to go into building pcs on the side you need to find a place that sells pc parts wholesale price.. ive found a couple of places that are pretty good but im looking for better ..ive found that the best way to do it is to buy through the net from a place out of state..and the reason for that is mainly because you dont pay taxes if you buy out of state..so any have any good place that they know of ?