To get Blacksmithing to level 300 is much effort. It is not that thing to make fast gold. There is always a lack of Blacksmiths though. Enchanters need rods of all kinds, melee classes look for Sharpening Stones and Weightstones with Counterweights, others buy Iron Spurs. Once you have learnt rare and epic recipes, people will always use your service to craft items.
To gain gold in World of Warcraft, you will primarily be grinding professions which are fantastic for receiving rewards. Mining is an example of a great profession at an early-game level. While Herbalism is actually the best gathering profession, the issue is it uses consumables which can make the profession rather costly, with the investment required.