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.
Recently, Blizzard provided their own WoW Token system for players to buy and sell World of Warcraft Gold. However, the constantly fluctuating supply and demand means that prices will vary. Consequently, getting the best prices isn't guaranteed, nor do you know when you'll make a sale. You also can't trade or resell any tokens you buy, as they become instantly "Soulbound".