Well there is 2 working methods to make more money with your 20$ in BTC, either you trade altcoins with it if you have good knowledge about trading, or you hold it into your wallet until the price increase highly and you can sell it then with good profit
holding doesn't really work with such small amount as $20.
lets assume price goes up to $800 in a couple of months then the profit will be $6 and I really doubt that $6 profit over a couple of months is a considerable amount of money anywhere in the world!
Yeah and even I don't think that altcoin trading will help him in making good profits from it and to make profits with that amount he need to wait for a long duration.
I disagree.
I don't know if OP is even considering this anymore but lets assume today someone wants to make a decision about $20. it is about 0.03
BTC and with that amount you can start trading multiple altcoins as testing and make 0.03
BTC profit in a month if you are willing to learn it.