After reading a bunch about selling photos online, I've decided to try what I think might be the simplest method for somebody with no professional photography skills and only a smartphone camera. I downloaded and installed the Foap app by Foap.com and went on a walk around my town snapping pictures of cool things.
I immediately started getting a few 4 and 5-star ratings on my shots but whether anything will actually ever sell is questionable. There are a lot of really good photographers on this platform and the site asking $10 USD for my amateur phone photos might be too much (you get 50% commission on anything that sells, therefore $5 USD).
I've checked out a number of online reviews from people trying to make money from Foap and so far it seems like a bust. Most people don't seem to be selling anything there as the platform is perhaps too saturated with sellers and not enough buyers. Regardless, it's free/easy to try and doesn't really take any of my time to snap a picture every once in a while. I will keep at it for a while and report back later.