Don't let the name fool you. It may be called online computer, but it is a legitimate physical store. Why of course you CAN buy their products online too.
Online computer is a division of 'online centre' established 1999. These guys offer a good (sometimes great, depending on what you're buying and when) price of quality products.
I've heard many complain about their lack of service or training as a customer rep, but I had no problem what so ever.
Last time I was served by Jim, I thought I lost my credit card in store, and was in a panic. He helped me out like a boss.
Now not all products are competitively priced so I'd check with other stores before I walk in, but only if you dont' know much about what's going on in the world of computing.
I also picked up a USB hub for i think 5? or 7 bucks here. Bargain cheaper than ebay I believe.
Great store, give it a go, whether you visit them online or physically.