It depends on the server, prices are always in flux...take note of them and get in on it!
As a miner, when you hit the higher levels you can get rare ores, gems and motes and really rake in the cash (now that everyone is in a scramble to level their JC or trying to get primals).
An herbalist gets the same satisfaction with things like swift thistle, goldthorn, steelbloom, firebloom, lotuses, netherbloom, nightmare vine and mana thistle(big money makers on my server). Not only that, some things like dreaming glory actually give you buffs while you're in the field!