Coins and token price go up and down because all cryptocurrencies in existence are running in a free market, therefore buying and selling of them causes the price to drop and rise from time to time. Besides supply and demand, price changes occur because of happenings related to crypto worldwide and of course it's developments. Manipulation also plays a huge role in the movement of price, Lastly, Newly released coins also causes price drop or rise sometimes to pre-existing coins.