Earlier quoted context omitted.
Probably you could just ask your kids, or ask around at a college campus, or google it, or check on craigslist (people sell weed on craigslist these days), or ask at a headshop. Also, I'm quite confident that someone you know, even in an extremely sober social circle would know someone who would now.
I won't go into details about why each solution you present is not optimal, because I have a better proposal. Make LSD and other drugs of similar effect legal. Have the government regulate the distribution. Put an exorbitant price tag on them and disallow buying-in-bulk. Make me sign that I am wholly responsible for what happens to me by using them (even though nothing adverse as lung cancer will, I'm sure). Give me…
How about a reasonable price tag?
Or how about blanket legalization of cultivation, possession, and use? I can get a tube of spores for "magic mushrooms" for about $10 and grow my own indefinitely. But for some reason this activity (the growing and using part) is currently highly illegal.
I don't need a license to brew beer and drink it myself or give it away. Why should it be any different for plants and fungi?