Starting a podcast, like making a YouTube channel or blog, comes down to telling interesting stories and building an engaged audience. I’m probably sounding like a broken record by now, but you need a niche that you’re interested in and there’s already a demand for. Come up with a list of topics you’d like to talk about and then search iTunes charts, Google Trends and other podcast research sites like to see what’s currently out there and popular.
For example, if you buy a $100 suit… perhaps you could rent it out for $25 for the night/weekend and someone locally is interested in just a cheap rental (because they don’t need to own a suit for the one or two times per year they wear one). After four weekends of renting the suit, it’s paid for itself. Now, whenever it’s rented out—you’re profiting for the remaining life of the suit.
If you're serious about making money online, start a blog. Blogging is one of the easiest and most sustainable income sources. As long as the blog is setup the right way, in the right niche, with the right content targeted at the right audience, and the offer is complementary to the content, you could make a tremendous amount of passive income from a blog.