If you ever wish to gain the top end gear in World of Warcraft, then you need gold. You will need gold to either buy the crafted gear and materials, which is the fast and easy way if you got enough gold, or you have to run the raids yourself in order to get tokes that you can turn in for your class tier gear. You may get some lucky drops from a boss but you need to remember that you aren't the only one wanting gear, and there are probably a few other people that will roll on the item that might drop. Of course many players don't have these amounts of gold or time to invest in the game, but if you haven't hit 85 yet, then you can make some serious gold using the Dungeon Finder tool.
Gold Making with Instance Farming
On the basic level, instance leveling can get you a large amount of gold, materials, reputation and materials quite fast. In the same way your character is leveling faster through instance leveling, the gold making will give you access to more gold. You are 5 people, and you will kill a mob much faster than if you would just go around solo grinding. Some of you think that because you need to share your gold with 4 other people that this is a useless method for making gold, but that's not the case.
The mobs that you will be killing are going to be elite, which means that they have more Hit Points than normal mobs, but they will drop more gold and have a higher drop chance of recipes, greens, blues, epics etc. You will also have blue and epic BoP (Binds on Pickup) items, which will make your leveling faster, this will also save you some gold because you won't have to buy new gear once you hit level 85.
Gold with Enchanting Materials
Another important thing when making gold while leveling in instances is the disenchanting ability. This is only usable if at least one person in your party got the profession. 9 out of 10 times someone will have it, so this isn't something you need to worry about.
What you need to do is to press the disenchant button every time an armor item drops, if you win the roll then the item will disenchanted automatically and you will get the enchanting materials straight to your bag. Choosing disenchanting is just like choosing greed, that means that if anyone chooses Need then they will get the item no matter how high or low they roll. Enchanting Materials is always selling for quite a lot at the Auction House, and people are power leveling their professions now with the Cataclysm expansion, so the demand is really high.
Making Gold With Grays
Most people just throw away gray items once they get it in their bag, but these gray items adds up to loads of gold during your leveling time. Same thing with Cloth but these should be put at the Auction House. Cloth like Wool can sell for up to 30 gold per stack. It's also very important that you have the largest bags possible.