What do you feed the fun guys to make em grow
That particular mushroom can grow on "waste paper products", eg, it can be grown on shredded cardboard, shredded office paper, toiletpaper, et al.
The substrate you need will be specific to the kind of mushroom you intend to grow, more or less. Some do best on sterilized straw (Button mushroom, several asian straw mushrooms), others do best on sterilized hardwood sawdust. (Shiitake, bunapi, etc..)
Again, this one does well on waste paper. I have lots of old cardboard boxes, and a paper shredder. I made shredded cardboard, then sterilized it inside a pressure cooker. To enrich it, I added about a cup of ordinary white flour, shook it up with the paper, then added the water and cooked in the pressure cooker. This made the cardboard sticky, as I basically added wallpaper paste to it. The added starch and protein from the flour will (in theory) assist the mycelium to colonize the substrate rapidly.
However, I have noted "Very good growth" on the aquarium, which is just straight up shredded cardboard wetted with 3% hydrogen peroxide (to discourage/kill mold.)
Time will tell which set of substrate works out better. I have 3 bags of enriched cardboard, and one aquarium of unenriched cardboard. Again, the aquarium is looking fine.
For the cheapskates among us that want to try and grow mushrooms:
Often, very fresh mushroom from the store will have bits of active "Feeder" mycelium still attached to the growth point at the base of the mushroom. If you collect these "ends", and then macerate them in a sterilized food processor along with some hydrogen peroxide, you can then pour the "Liquid culture" into some sterilized spawn medium (such as milo, birdseed, whole wheat berry, etc...), then seal it up in a jar for a few weeks to get actual "seed spawn" going for that variety of mushroom. After that, you need to process your actual growing substrate, sterilize your work area and your grow bags/chambers, and then mix everything up and seal it up against outside contaminants.
Some varieties of mushroom are more difficult to grow than others. Blue oyster is "Super duper easy" on the difficulty scale.
I first learned of this technique (liquid spawn recovery) from shroomery.net (which is not linked here, because it is a psychedelic mushroom website), but it works just fine for many varieties of table mushroom.