Unrelated, but have you ever tried mescaline via san pedro? One of the good legal psychedelics if you're thinking about shrooms.
I've never used any psychedelic, legal or not - a quick Google makes mescaline via cactus sound fairly complicated..
Half-day trip on san pedro in college... good times
try camping in Joshua Tree with a ziplock of peyote buttons and a gallon bottle of cactus juice. I lost my fucking mind there in the desert sand, and then found it two days later, in better condition than when I left it.
For all drugs, it's quite possible that online offers better quality. I've known cocaine users whose local dealers only sold shitty quality, afaik I don't know anyone who has bought online but it might make sense for them in that case. And drugs like weed, might well be that you want a choice of strains whereas most dealers just have whatever they managed to buy, not a supermarket range of choices.