
Certified GKH Gardening Expert
You can buy spores from reputable dealers online or mushroom growing kits. You won't find plants. You also can grow mushrooms from store bought mushroom ends. These articles should help:
https://www.gardeningknowhow.com/edible/vegetables/mushrooms/propagating-mushroom-ends.htm
https://www.gardeningknowhow.com/trends/get-year-round-mushrooms-with-a-mushroom-grow-kit
https://www.gardeningknowhow.com/edible/vegetables/mushrooms/grow-mushrooms.htm
https://www.gardeningknowhow.com/edible/vegetables/mushrooms/mushrooms-in-coffee-grounds.htm
https://www.gardeningknowhow.com/edible/vegetables/mushrooms/making-a-mushroom-fruiting-chamber.htm