It is almost impossible to predict how much a potentially-brandable name is worth. Someone might want to start a business and think "XISTU" - this fits my thinking absolutely, and you might gt US$5000 or more. Someone else might take an analogous view, not for his or her personal use but to profit from my first scenario, without knowing how long it might take to sell it. So, they'll possibly offer you US$500. Very difficult to know since it's not a tangible word.