There are rarely any seeds for Salvia divinorum. It grows and propagates from cuttings almost exclusively. Even when there are seeds from a plant, rarely do they grow; the average viability rate is about 5%, and they do not remain viable very long either. The best way to get a Salvia plant for your own, is to buy a plant, or to get a cutting from a friend. Even then, though, there is much to do to get it to stay alive, and you can find that information throughout this website.
Either way, if you are intent on getting seeds for this sacred plant, rather than trying to acquire a cutting, you have to be sure of the source. We have found more than one online store offering what they claim are Salvia seeds, but when we have purchased them and tried to grow them, the one plant we got to grow from the handful of seeds was not a Salvia plant at all. Next time we acquire some specimens, we will take macro photos of them, so that you can positively identify the seeds before you plant them. Look for this information on this page sometime soon.
Know that this plant grows on a mountainside, in misty, warm weather, as if a blanket of moisture surrounds this plant almost all the time. This makes cultivation extremely difficult, and not only is it almost impossible to find a viable Salvia divinorum seed, it is even more impossible to keep the seedling alive once you manage to find a viable, genuine seed from this plant. The only hope is to cultivate the seed in a greenhouse, or in a humidity tent that keeps a blanket of moisture available all of the time. You can over water this plant extremely easily, but you can never (at least we have never found) over-humidify the plant.