Go to your local 7-11 or grocery store and look for the free magazine stands (that usually have the real estate magazines in them). There's a free computer magazine called "Vancouver Computes!" which has a bunch of ads and prices inside (as well as some decent articles).
Looking inside this month's copy, here are some stores and links:
www.[b]FlyComputers[/b].com (they have 2 stores, one in Vancouver at 57th and Cambie, and the other in Burnaby at the corner of East Hastings and Willingdon).
In Richmond there's
MicRock Computer Inc. (
www.microck.com) 5060 Hollymount Gate
Another Richmond company is
Addax Computer Inc. (
www.addax.bc.ca) near Ikea Furniture on Bridgeport Road.
Another place I'd personally recommend is
Techmaster Computer Ltd. in Port Moody. I bought my motherboard and processor there, and just recently bought 256mb of Micron ram there for 100 bucks (cdn obviously, including taxes).
EDIT: Of all the places mentioned above, their prices are usually within 10 bucks of each other on parts in the $200 to $300 range, so the one that's closest would probably be the best (but phone around just in case). I like doing business with an actual store rather than an online place, because I have somewhere I can take any problems with the parts (and I know that they must follow Canadian and BC laws).