On the internet you can hear about the "metodo croce" (I don't know the English translation, maybe cross method) that promises to earn money with roulette.
Example:
If you bet on red and come out red, you make the next bet on black.
If you bet black and it comes out red the next time you bet twice on black, if you lose bet qudruple on black and so on.
So when you win you will be able to recover all the losses and have a profit.
The problem with this method is that you can lose up to 20 times in a row and even if you bet only one cent it will become more than 5000 euros or dollars.
This script proves that you always lose! sometimes it takes a few hours, sometimes a few weeks, but sooner or later you always lose.
Also check the money and time, you can have earnings (which sooner or later you lose) but in very long times.