Apparently it's not illegal to sell even magic mushroom spores, and several sites will sell you syringes with enough inoculate to make a couple or more spawn bags. Once you grow them, unless you are in one of a a very places where it has been decriminalized, you have a bigger felony than weed on your hands.
The syringes seem to run about $25 a strain, but if you buy 3 or 5 you get a discount. Then you have the cost of spawn bags and a grow box. All in a first batch should cost you about $100, less if you mcguyver it and are willing to risk infected batches, but some of that can be used again.
The whole process can be found on youtube. It figures, they banned cannabis channels for a while but are still allowing magic growing channels unfettered.
I'm actually going to try growing, but only non-psychoactive strains. For now.. lol.