Shopping for tech stuff in So Cal is great because we get all the latest gear the minute it gets off the boat from Asia. Staples and Best Buy do not have the selection they once did as electronics sales shift more onto the Internet. People on the East Coast pay more for the same stuff because it must be shipped across America first.
By far the biggest, cheapest, best place to get tech gear is Fry's Electronics.
And what don't they sell? Computers, parts, printers, games, appliances, toys, gadgets and enough electronic components to build a hundred Artoo-Detoos. It's hacker heaven and where all the tech savvy folks shop. They have nine gigantic stores in Southern California. Unfortunately none of them are near West Hollywood or the West Side because they need so much real estate. It is a trip to make it out to them but it is worth it. You just better know what you want because most of the workers are immigrants and don't know much about electronics. The woman you just asked about network adapters might have been living in a ditch in Bolivia last week.
But the people at the memory/CPU desk are always VERY knowledgeable. Even PC experts find CPU and memory modules confusing and fast changing. It's easy to buy the wrong thing and the components don't work together. The folks at the PC parts desk have not steered me wrong when it comes to assembling computers from scratch. If you are too far from one of the locations listed below you can always shop at Frys.com
but you won't have anybody to ask if you are buying the right thing.
Another neat thing about the physical stores is that each one is done up in a different theme. Fry's knows people sometimes have to spend a lot of time in line at Christmas so they make sure each store is full of unusual sculptures and displays. The Burbank store has a UFO crashing into it's entrance and a Sci Fi B-movie theme inside. The computer department is help up on the suckered arms of a giant drooling octopus! The Woodland Hills store is theme as "Alice in Wonderland" and visitors seem to be falling down the rabbit hole as they enter the store. Kids love it!
For strictly online shopping I recommend NewEgg.com.
There are several other sites that are just as good but New Egg is in Whittier. That's in LA just 12 miles from downtown. They can deliver almost anything in a day or two even with the cheapest shipping. Plus they get everything new and nifty the minute it comes off the boat from Asia. Long Beach is where all the Asian imports enter America. Why buy from an East Coast site that must ship electronics cross country just to get back to where it was originally imported?