The discount ranges by product. Some things, like high-end video cards, have very little discount as the majority of the money goes to the manufacturer. My best deals are on accessories and cables, of course, as they are the cash cows of the tech industry.
I get the discounts because I am starting a gaming website selling consoles, games, and accessories for Xbox, Xbox360, PS2, PSP, GC, GBA, DS, and PS3 and Wii when they come out. I've been working with my local gaming community for the last 10 years, growing from about 50 gamers to about 500 in the last few years, so I figured might as well make a business. Plus, I can't get some of the toys that I want locally, so now I can.
CCGR, I might have some hardware to get rid of via your site, I'll have to wait until I get some pictures up.