Yes there should be a circulation and it is better to keep on selling bitcoins when the price is high, and re buy when the price falls down, I keep on buying bitcoin when the price falls down and that is the best way to earn profits out of profits.
Well Regardless in buying bitcoins and selling it this methods are common in this forum actually trading it will be great too, and I myself buys a lot when bitcoin goes down I think I will buy bitcoin when it is below $314 dollar for further getting much bitcoin when selling!
Yeah, buying bitcon when the price goes down is really good one. so you can sell it when the price goes up and got profit from it. that's why i also buying bitcoin for it.