There are several ways to make gold in Wold of Warcraft without having a personal army of crafters or spending hours farming. The methods that I list below can be used by any level character and only requires a small bank roll to get started.
Vendor Items One of the easiest ways to make some quick gold is from limited vendor recipes and items. All the major cities have vendors that sell recipes for a few silver that most people don't pay very much attention to but surprisingly these actually sell on the auction house for several gold each. Just head over to the cooking,enchanting,tailor, heck just about any crafting trainer and buy any of the limited items and post them on the AH for 5-25g on a 24 or 48 hour auction.
Pets There are a bunch of pet vendors through out the game. Players love these vanity items and buy them off the AH all the time. You can find a good source of were to get a bunch of these pets in the linked information at the bottom of the page.
Converting There are several items you can buy and trade in for another item which you can then sell for a profit. One of these is the Frozen orb. You can usually buy these for half the price of the top selling Eternal. Get a port to Dalaran and turn the the Orbs in for Eternal Fires then sell the Fires on the AH for a nice profit. Another good item to trade up is Savage Heavy Leather. You can buy 10 of the heavy leather then head to the Twilight Highlands and trade these at the vendor for Pristine hides. On most servers you can make anywhere from 40 to 100g a piece on the hides.
Breaking down items or stacks You can often buy Eternals, Primals, or Essence and break them down into individual pieces and sell them for more then you would get for the solid piece. An example would be buying a Greater Cosmic Essence for 12g and breaking it down into 3 Lesser Cosmic Essence and sell them for 5.5 to 7 gold each. You can also do this with items that people are selling in stacks. A great example of this if the common gems used in the JC dailies. You could buy a stack of 20 Jaspers for 200g and break it down and sell singles for 15g each or stacks of 3 for 45g. Most players will just buy what they need instead of buying the full stack even though the per item price is cheaper for the stack. This method works really well with flask, potions, exiliars and buff foods.
Flipping Flipping is just buying under priced items and reselling them at the normal or higher prices. Flipping items on the AH can make you a ton of gold but requires some research before you get started. You have to know your auction house's normal prices on items and what sells on a regular basis or you'll end up with a bunch of junk in your bags or bank that you can't get rid of. The safest items to flip are crafting mat's such as clothes, ore, bars, herbs, inks, leathers, and enchanting mat's. These items are always in demand and you can find under priced auctions from people that don't really pay attention to the normal prices and just post them. Also if you see that the supply is low for any particular item and the prices are not to high you could buy them all out and re-post at a higher price. You want to be careful not to get to greedy and make the price to high or players will just wait to buy them. If you have the bank roll and are willing to take the risk you can look at epics, trinkets, rare pets and rare recipes. You can make hundreds or thousands of gold on these items but you can also get burned. Basically you can flip just about anything you just have to get some knowledge on what sells and what your servers normal prices are. Once you get this down you can make huge amounts of gold.
These are all great gold making methods that don't require a lot of income to start and the more you use them and learn your AH the more gold you'll make. There are a lot of sources of information that can help you find the vendor recipes and pets on the web. You can also look for the Auctioneer addon which is a awesome tool for flipping items and many other thing.