I tend to just continously buy lelveling herbs for cheap and stockpile them. I try to keep at least enough to max out 4 toons at once. If you buy over several weeks at only low prices, alchemy is cheap and fast to level.

Goldthorn...though is a major pain. Never enough on AH and pain to farm.

I use theunderminejournal.com to notify me when any gets posted so I can buy it.