My item. I'll sell it whatever price I want. If I want to undercut I will under cut if I want to overprice I will overprice. Some people want a quick buck to make so they will undercut just so people will buy them and sell them at a higher price. I know that will happen and frankly I don't care. I only do this when it comes to crafting materials because of this one glorious thing se implemented: ventures. Send them out for a hunting venture, get them to hunt the stuff people need like allapaku(misspelled) eggs. Wait for an hour or 4. Get 20-100 (depending on how many ventures you made) of them mixed of high and normal quality. Sell them dirty cheap. Watch the market suddenly collapse because of it. Buy them all at the collapsed price. ?????. Profit. There's more to it but that's the gist of it.

Honestly it gives me sadistic pleasure watching the market collapse especially if the thing I'm gonna collapse is something overpriced in the market board.