There are no "Best coins to buy". I recommend that you do your own research into some alt-coins and find something promising.
Invest.
Profit.
Well, there are coins that gives a lot of profit so for me thats a best coin to buy. Bitcoin and eth is th top choices but this market is consist of many good coins, its right that you make your own research so you will find out where to invest on your own and you will be more happy because you are learning while earning.