I would suggest that you do what a friend of mine did the first time that he bought. Buy some 5x, some 10x, some 15x, some 20x, and some 45x.

Start off slow! You don't want to have a crazy, 45x experience your first time and get turned off Salvia. Start off with 5x a few times, then go to 10x, etc.

You probably don't want to get the leaves, because you would have to smoke many bowls of them to get the effects, and that's no fun.

I don't really know any good Salvia websites.. I think that http://www.Iamshaman.com is supposed to be pretty good.