Buy and sell of course it is a nice thing. If you can not buy coins at Low Prize, you will lose your money if you sell coins. At the same time, you must buy coin by verifying the condition of the market and you must buying the high rate because the sales of the low amount. Of course, depending on high and low price. No one ever wants to sell at a lower price and sell them at a lower price, if they need to hold the coins for a long time.