So I think that the best way to earn extra money is the way of investing in a crypto-coin that has been proven over the years, which already brings good profits to many.
It's proven and tested which we have been able to experience.
But also be careful with projects that may good look to you. As always, DYOR, because it's the best thing to do if you're finding out a project that you may think is good for investing.
NFT, ICO, IEO and other type of those, they've became a source for extra money for many investors. But also be aware of scammers are also into those.