As you are surfing the auction house you will see a lot of things there that are marked wrong or even to low. The low based products can be seen after about 3-4 days of checking prices.
One item that I have been keeping an eye on is maelstrom crystals these items usually sell for just about 200 gold on my server during peak times. So often will I find myself buying these at about the price of 170 gold. Then to just wait and repost them.
Depending on the actual cost sometimes I will go as far as to just buy the market out and just reset it, but that's a different post. Usually when I am working on a specific profession then is when I see price fluctuation. So stick with it and you will soon be making tons of gold as well.
Just wanted to give some direction on what others are saying at phat lewts gold be sure to see what he has to say on the same topic.