There are lots of possible options for making gold once you hit level 70. If you have professions you can make money by selling your supplies, crafted items, enchants, or whatever your specialty provides to your character. You can farm for certain items like cloth, primals, and vendor loot. There are even ways to make money fishing. A big way to make money is by doing quests with your character. Chances are that you didn't finish all the quests in the Outland before you hit 70 and if you decide to do those quests now you will get gold instead of experience. Questing at level 70 can equate to big bucks. Here's an example of the kind of cash you can make while questing.

Case Sample: Questing for Gold

Place: Netherstorm
Classes: Priest and Rogue
Time: 2 hours and 15 minutes
Number of Quest Turn ins: 25

Items Looted: 9 stacks of Netherweave Cloth, 14 Motes of Mana, 5 "green" items
Money from quests: 268 gold each
Money from vendor trash and sold quest rewards: 46 each
Total gold made: 314 gold each (not including items)

TOTAL GOLD MADE TOGETHER: 628 gold

My rogue friend and I set out one day to make some gold. We had completed a only few quests in Netherstorm and decided to head to Town Square (located in southeastern Netherstorm) and pick up the quests that can be found there. We completed all the quests from Town Square, along with one or two stray quests we had from before. The quests were very simple and easy to complete, we stayed within a very small radius of the quest givers. By the time we had completed all the quests we had EACH MADE 268 gold from quest turn ins and about 46 gold each for sold vendor trash and quest rewards. We both made 314 gold, for a combined total of 628 gold, plus the items which are not figured into this value. We accomplished this in only 2 hours and 15 minutes.

If you are short on gold don't overlook the possibility of making it through quests. As the above example shows, you can make quite a large amount of gold in a short period of time. If you do decide to quest for gold choose your quests wisely, don't waste time doing time consuming low drop rate collection quests. Also, consider researching what factions are obtained by doing certain quests so that you can focus on quests for gold that also help you raise the factions you want. Finally, try to find a a gold making buddy. Even if you have to split loot, you can usually kill mobs faster and complete quests much quicker.