Johnny,
You will probably be expected to handle customer support as well as exchanges and returns, so you'll be surprised as to how much time it would actually take up.
The best way to shop for computer products, at least that I've found, is to visit
www.pricewatch.com
As long as you know exactly what you want, and how to interpret what the vendor is selling, you will not beat the pricing that is available.
Computer parts are getting to be a pure commodity....the lowest price is what so many people are looking for.