xD I can tell you don't know anything about merchanting.
Try to buy a Rune Scimitar at Maximum price. You will buy it for medium. Why? Because you buy from the person selling cheaper and sell to the person buying for more. So, when I buy a set for 2k above medium price, I have priority relatively to the ones buying for medium, as I offer more. When selling I sell for 10k less as I have priority over the people selling for Maximum.