If you like that, then the next level of difficulty is creating your own fruiting kits using mushroom spawn. I'm in Australia, but you can buy it from somewhere like here if you're in the US: http://out-grow.com/live-mushroom-spawn-c-12/. You basically mix the spawn with treated straw or sawdust and put it in containers, the spawn will colonise and shortly after you'll get mushrooms. Most sites will recommend you sterilise or pasteurise the straw/sawdust (they call this the substrate), but the easiest way to grow without pasteurising/sterilising is using paper, see here as an example: http://re-thinkgreen.com/2016/02/24/mushroom-kit/
Stamets is regarded as the guru, but I think "The Essential Guide to Cultivating Mushrooms" (https://www.amazon.com/Essential-Guide-Cultivating-Mushrooms...) is a better starting point for the beginner. You don't need to be as much of a clean freak as he makes out, there are plenty of low-tech methods.
I'm in the process of writing a short guide on growing shiitake at home, it's harder than oyster mushrooms but once you get the basics it's pretty easy too. It's pretty crazy the amount of mushrooms you can grow with basically no space, you can see my son here with some we harvested recently: http://www.mushroom.guide/
If you're in a bigger city, there should also be day courses to learn the basics, search for something like "grow gourmet mushrooms [cityname]"