This totally depends on your skill, labor or expertise and expense of course. Like if you have a hand in cooking, you can sell your recipes or own a bakery. If you are expert in management, then create your online site and start selling your products. One can become publisher for their own books too.
Keep in mind, it can be easy but should be innovative to create its own space in the world i.e. recognition. This way you can easily select what’s easiest and affordable