if you have no trading skills it will be a waste of your time and money. there is nothing wrong if you want to earn money from trading, but you have to start by learning some techniques and also how to choose trading assets. if not your small capital will just disappear without you feeling any advantage.
maybe if you are interested in investing, you can buy Bitcoins consistently with your $ 20 in a certain time interval. so you can have quite a lot of Bitcoin when you are strong enough to hold the asset.