You should consider getting the addon Auctioneer.
It's pretty neat, it scans the auctions on your server and then every time you put something into the auctionhouse it automatically slightly undercuts the lowest price on that object so it will sell!
You can push up the price a little bit if you expect the item is popular and the lowest price will sell quick. Then you can sell it for a bit more when people buy through the cheap stuff.
http://auctioneeraddon.com/