Sometimes this will happen and the but price is much higher then the sell price. That means people are not willing to let go of the tokens for too cheap and people making offers are trying to get cheap offers and are not ready to pay the buying price. You need to remember that you don't have to use the prices that you see there. You can add a custom buy oreder and maybe meet hald way between the buy and sell price and then wait. Your chances that someone will decide to sell at the price you offer will increase. ALways remember you can make your own offres too. This is how the buy and sell order is filled to begin with.