I suggest you to buy NEM,even the price is above a dollar but it is worth to invest and the price of NEM in 2018 will explode I hope the price will reach upto $10.If you still looking for the coin under one dollar then you can pick your coin based on the rankings of coinmarket cap.S you can go to coinmarketcap.com and select the coins from top 100 ranks.
There is a coin named Siacoin which price is too low but it looks more potential in the future and it currently ranked in top 20 coins of coin market cap.So,don't forget to checkout that coins also.