I think another thing you should note, to do with the auction house. Everyone needs an equal chance to sell items if they need money. Don't undercut some one on the auction of a same item just so you can sell yours faster.( I tend not to buy from some one who listed theirs at miniscule amounts lower than the person above.) It works like any other market. Things should be priced accordingly.
And on the other side of the spectrum, please don't list items for astronomical amounts because you don't see one on the auction house. Chances are some on just bought that item.

I suppose vanity items are an exception seeing as how they are extremely rare. But crafting items and low level items should be priced according to how many are on auction and what price others have it listed at.

We all want to make some extra cash. This can be done in fair manner.