I guess this is like common sense but Im guessing most people dont do it, at least on my server anyway based on what Ive got the past few days.
Simply clicking the search button on the AH and sorting to see the cheapest items, you find mostly junk or low lvl stuff but on occasions you find something good.
Most of the stuff I have found are marks, shards or trade goods people expected to get higher bid on. Sometimes they only get 1 bid and you get something cheap.
If you bid on everything that is worth something you can get a decent amount of stuff that you can sell at higher price. I guess this is more usefull for low lvls on new servers who are trying to make a bit of money everytime they visit the AH.
Higher lvls tend to auction stuff off at any old price sometimes so its worth trying.