I used to make a mint buying items low and selling them high on the auction, but i got tired of sitting around the org. Recently I discovered a little trick that lets me grind/quest and troll the org trade channel.

All you have to do is create a new chat window and join the orgrimmar trade channel "Trade - Orgrimmar". This way you can go about your business AND keep an eye out for good deals. When you see something you like just relog as your alt. This works especially well late at night when people become desperate to unload their rares, as nobody is on to buy them. Just make sure your Auctioneer scans are up to date.

If you dont have auctioneer.... get it. Once you have a decent amount of capital you will make money like crazy and pick up some sweet gear at even sweeter prices.