before you want to buy now and trade, you need to determine in what site you want to trade. i think there is many best coin you can buy but you need to search by yourself so you can found the best coin that you want. in bittrex, you can look in the list of the coins, usually i am search the coins which have a good volume but its in the down/red sign, i analyze it to know is it a good time to buy or not.