Learn to use the Auction House when you are WOW Power leveling, both for buying and selling if you have nothing else to do except World of Warcraft Leveling.
Install the Auctioneer addon and use it to your advantage in the Auction House during the process of WOW Leveling.
Before you pay for WoW Powerleveling, bargain with the seller. Remember do not pay at full price.
You’d better post a buyout price on auctions during the process of World of Warcraft Leveling.
Unless the item is heavily discounted on your WOW Leveling, most players who need fast WOW Power leveling will not bid on an auction with no buyout. And then it usually sells for a fraction of what it could have gotten. Only price your item properly when WoW Powerleveling, will you have more trade at a higher price and get money quickly for your WOW Leveling.
When you have saved around 5 (and you will quickly, due to having taken gathering professions), you can start investing to WOW Power leveling. Buy cheap items on the AH and then re-list them for a profit when World of Warcraft Leveling. Only buy and sell what you know about WOW Power leveling, and test your theories in small quantities.
Taking two of the gathering professions: Mining, Herbalism, and Cheap WOW Leveling or Skinning is a surefire moneymaker.
You don't have to Fish during the process of Fast WOW Power leveling, and fishing is not to everyone's taste, it involves a lot of sitting and staring at a bobber, but fishing can become a good source of income as your WoW Powerleveling.
Crafting professions are money sinks for your WOW Leveling if you pursue them.
Keep in mind "Do not take crafting professions until you are over WOW Leveling 40." You can get many useful materials at that wow power level.
The crafting professions for World of Warcraft Leveling will not provide any profit margins at low wow power level that exceeds the profit from selling the raw materials (ore, herbs, and skins).
Generally, you may lose value when crafting good for your fast WOW Leveling. It is common that the raw materials are worth more than the product.