You can make money online by doing freelance work, starting a youtube channel and monetizing your videos, writing content and articles for other peoples websites.
Those are things you can do legit to earn money online from home without investing any money.
If you want to invest around $50.00 per year you can also start a blog and write your own content for your own blog and those blog posts will continue to earn you money over the years after your write the content.
I make money by blogging and the investment of the $50.00 per year in hosting and domain fees is worth it as I make more than enough to cover the hosting and domain fees and money to pay other bills as well.
It will take time though for a blog to start earning money. It took me 5 years for one of my blogs to take off and start making more than the hosting and domain costs per month.
I earn money through Adsense, when someone clicks on an advertisement on my blog I earn money.
I make this money through my website and adsense even when I'm away from the computer or asleep.
Earning the money through your website and adsense is a long term thing and will not happen overnight.
So if you start a blog to make money you should expect to wait awhile to get regular payouts.
Earning money through adsense and a blog is not an overnight thing and takes time and you have to work hard in the beginning for little to nothing in return but after the times passes and it will anyway your hard work will pay off for years to come.