When buying cryptocurrency dont buy cryptocurrencies which are cheap in price but buy cryptocurrencies which have a huge Market Cap.
Yes! Buy Cryptocurrencies according to their Market Cap because if the coin is cheaper that doesnt make it cheaper.
Market Cap = Total circulated coin (Number of coins in existence available to the public) + Price of Coin
Let's take real an example,
Here, Ive taken 2 coins.
1.) Ripple
2.) Dogecoin
Now as you can see the difference between their Market Cap, Total Circulated Coins and also the price.
According to the price, Dogecoins looks cheaper well but Dogecoin has a low market cap compared to Ripple.
It also depends on the Total Circulated Coin and if Dogecoin had a price of $0.5 then it could have been competitive.
So I hope you wont go for coins with cheaper prices instead go for coins having a good market cap and Total Circulated Coin.
If you still need some suggestions about which cryptocurrency under $1 is a good investment for 2018 then here are the coins which I would recommend.
1.) Ripple (XRP) - Currently $0.30
2.) DigiByte (DGB) Currently $0.03
3.) Dogecoin (DOGE) - Currently 0.003
4.) SiaCoin (SC) - Currently $0.01
5.) NEM (XEM) - Currently $0.20