Even if it was someone desperate for money, they still tried to sell a very dangerous drug to another human. That’s not ok, in my opinion.
That’s where I draw the line: if you’re only harming yourself you need help. If you’re trying to fuel others’ addiction, it’s jail. At most if it’s clear that the person has a huge drug issue you could force the rehabilitation center in that case as well (but again, the first time. If you still sell meth after that you’re asking for it).