I know quite a bit about salvia, I actually spent some time talking to Daniel Seibert, the leading expert on Salvia Divinorum, almost 20 years ago

I actually purchased salvia from his site lol.
It's a bitch of a plant to cultivate from what I've read/understand, and as stated you can order seeds but there is a very limited window for viability with them and no guarantee the source is good stock of seeds either.
Salvia can be consumed orally, smoked, etc, and often it's concentrated to bring out more of the effects.
You MUST HAVE A BABYSITTER WHILE CONSUMING SALVIA. BE SAFE. You will literally exit rational thought while consuming it, the potential to do something accidentally is real, just please be careful.
It's a shamanistic plant, it's not meant to party with.