If you're ready to enter the ecommerce fray, you could sell your own stuff. Of course, along with selling your own stuff on your own website comes a whole slew of both responsibilities and technical configuration and requirements. For starters, you'll need a website and a hosting account. You'll also need a merchant account like ones offered by Stripe or PayPal. Then you'll need to design that site, build a sales funnel, create a lead magnet and do some email marketing.
Are you seeing the possibilities here? Think about what book, or series of books you could write to help people in your field of expertise? You might start with an eBook offered on your own website that covers the basics. Use the eBook as an opportunity to tell people about your more in-depth book on Amazon and finally, follow through with an advanced book offering.
Great list. I have another to add that’s almost as easy to do as going for a walk! Provide a litter cleanup service outside commercial properties for property management companies. The work is done on foot using simple hand tools. I started this service in 1981 as a side hustle and quickly grew it into a lucrative full-time business that I still operate. I share my experience with others in my book, Cleanlots, as well as offer free support.