One excellent web site that I've encountered is woot.com. Basically, it's a web site where every day, they sell something different. For example, today they are selling a 6 GB USB drive for $49.99!
I purchased a Logitech wireless keyboard/mouse set for $19.99 one day, and that was a great deal.
It's very random. Today it's a USB drive...tomorrow it could be something completely random and unrelated. Definitely worth checking out and bookmarking!