Buy and sell at whatever prices you want. It doesn't matter. The marketboard is PvP, and you are free to do whatever it takes to sell items. If it costs you money, then so be it you do so at your own risk, and other people can snipe it if they think they can do better.
I sell at whatever the going rate is. I do not care about the servers inflated prices. If a server has nothing but inflated items, people will not purchase items on that world. This is the case for most worlds on Dynamis. Are you going to spend 20k+ more gil per item you need out of laziness? Some people will. I wager most won't. I don't sell at inflated rates. If it makes people angry, they're free to buy my items off the market and repost them.