Like almost everyone above you say you have to start with an amount of money that will not affect your life if you lose it. My advice is to start with a small amount and save it for a while. This is because at first, if you don't have experience.
$100 is a lot of money to start with.
I think $ 100 is the minimum amount for investment in cheap and promising altcoins. And it is better to hold these altcoins on a long term.