In most states in the US it’s perfectly legal to own and possess spores of psilocybin/psilocin producing mushrooms, what’s technically illegal is growing and harvesting them. There are quite a few legal (check for your state) online sites where one could acquire spores for… mycology.

Also, it turns out, people have figured out how to grow a variety of mushrooms at home, culinary or otherwise, using different “teks” and it’s gotten to be pretty easy. If one were to be truly interested some simple searches would most likely turn up any information needed.