There is a rising number teachers who are making extra cash by selling their worksheets online. You can also sell your worksheets and lesson resources on the internet. Many digital marketplace have popped up helping teachers to sell their resources.
With the increase in workload teachers are finding it hard to create their own teaching resources. The alternative is to purchase quality resources online. Marketplaces like TES and TeachersPayTeachers have made very easy to buy and sell worksheets and other resources online. All you need is your own resources. It will take minutes to upload and set up your shop. With simple systems set up, teachers can now earn extra income from all the hard work they have put in in creating teaching resources over the years.
If you are in the United Kingdom, then TES Global will be the best place to sell your worksheets. Join the forum on TES to get a better picture of how teachers are making money selling their teaching resources.
Best of luck.