This is the most common gold cultivation strategy throughout World of Warcraft’s life cycle. However, this may be a long-term strategy, so if you need gold right away, you may need to consider some other options.
All you have to do is collect enough gold and buy dark and assassin knives from the auction house. These will flood the market because of how many people will be playing games in the early stages of launch. Then, you can, hopefully, sell them in a few months when the surplus of goods falls and demand rises. This should bring you considerable profits, but it is also a longer-term game.
To take this a step further, you can use several plugins for auction houses. Both the auctioneer and Aux will help you find out what you can buy below market value and give you a chance to sell them at a higher price!