Arguing supply and demand when I see people selling stacks of things for 1g, and losing money in the process to AH taxes. Where is the economy 101 sense there? Why in hell do people sell things as cheap or cheaper than vendor and lose money?

I understand supply and demand, what I do not understand is selling items for less than the single value of the materials needed to craft it, that is a horrible way to spend your time and money.

What the OP is trying to avoid, is people undercutting and selling things cheaper than what they would sell if we charged for the mats required to craft, not to mention the labor and gathering time.