This is definitely a common misconception of people entering the crypto market. Many believe that in order to buy any coin they must buy a whole number quantity instead of knowing they can buy a fraction of a coin, say Bitcoin.
This misconception is the reason some alt coins get pumped solely because they are super cheap even if they have no actual basis as to be a reputable coin.
RE: No, You Don't Have to Buy a Whole Bitcoin (Thoughts and Review as well)