well salvia isnt approved by the fda for human consumption, so i'll assume its illegal to sell or market it for such a purpose.

but it can legally be sold as incense or for any other concievable purpose other than consumption.

now if a person buys it for 'incense' yet decides to consume it i doubt they are breaking any law because salvia and it active chemical salvinorin-A are un-shceduled substances. but if a person is an idiot and chooses to use it in a public setting and makes an ass out of himself he could proberly only be charged with public intoxication or disorderly conduct.