Hmmm, all this fuss over pixels. :) I myself autoprice but have a deal of the day section. I enjoy placing a high item at 50% or more off, it's fun for me and fun for the person who snipes it. There is no better feeling than looking up an item you really want and seeing one for extremely lower than the rest! What a rush! And as much as everyone complains, I know you sure as hell buy that item. Lets remember that it is a game and we are here to have fun. Me, I love the undercutters - it's like xmas!
I was going to make a comment about that but beat me to it.
If an item is actually rare and someone is trying to drop the price you could always hold it in storage for a time and wait for the price to go up.
Supply and demand people. When people vend and restock a lot more items will be in play, and everyone wants to sell their items first. More supply means prices will go down, less supply means prices go up.
I don't think it affects the economy that much. If it's REALLY low, someone will snag it, sell it at its original price and get profit. I've done it before. I've had items rot in my shop, got sick of them and lowered the price by a lot and before I knew it someone had snagged it. The economy was absolutely fine.