Here in Cali, it's completely legal. All you have to do is walk into a headshop and say "Hey, I need some Salvia..what's the strongest extract you've got?". They sell it as "herbal incense" in this little pink plastic container, but of course the shopowners know exactly what it's used for, they always wink and say "have fun".

If you have access to a car, and you can drive to a neighboring state, just set up a P.O. box in that state, order it from one of the many online vendors, then go pick it up.

Salvia will not harm you in any way, except for the obvious carcinogenic chemicals caused by burning ANY plant.