EDIT: 2 things based on the last couple replies:
1. NO SOURCE DISCUSSION, even for legal substances like salvia. The prices should probably go, too - they're not really needed, nobody here can tell you how you should manage your personal finances, let's just talk about the drug itself kay? Not to be elitist or anything, but seriously - if you need a specifically drug-related website to find a 'source' for a common, legal plant, maybe you should give extremely intense quasi-deliriant psychedelics like salvia a pass for now
2. DO NOT do salvia if you're just bored and out of weed, imo. It's nothing at all like weed. It's not really recreational in any meaningful sense - it's not euphoric, it's not a drug to take to see some eye candy and trip out for a bit, it's more like a cross between an intense, rough, short acting psychedelic like 5-MeO-DMT and a deliriant like benadryl or belladonna.
I do know people who like it (never did much for me, a few weird and interesting but not particularly fun experiences and a lot of duds with little effect), or at least are glad they tried it... Its effects are very unpredictable but common ones include weird, hard to describe body sensations (a popular analogy I've heard is that it feels like sections/segments/slivers of your body or a part of it seeming to move or rotate in different directions), visuals ranging from the room in front of you breaking down to complex geometric shapes all the way to full blown out of body experiences and entity contact. It often borders on, or dives right into the weird, the horrifying, the delirious - more like a creepy dream bordering on nightmare than a psychedelic trip in many ways. If you're the type who finds any new altered state inherently fascinating and needs a good reason not to try it, or if any of that sounds appealing to you, give it a shot. Otherwise, pass.
Unless you can get fresh leaves and want to try a traditional oral quid instead of smoking, get an extract for sure. You are supposed to hold a hot (preferably torch lighter) flame directly on the leaf the whole time you pull and hold the (hotter than pot or tobacco) smoke in for 20-30 seconds each hit, and many people need a couple hits even of strong extract, so smoking the non-extract leaf is generally not worthwhile.