If you’re running your own blog on a certain topic or niche publishing an ebook can be a great way to earn money. Websites like Nexus Notes or Stuvia let you upload your notes to sell. They will take a tiny percent, but you can make a lot. Make sure that your notes are typed and not handwritten.
Renting out your home or even a tiny corner of your garden is a great opportunity to earn some extra money. You can advertise on sites like Airbnb, or through word of mouth and local classifieds.
If you’re gifted for design Logo design is another way to make money online. Be sure that it doesn’t take over your life!