Things like learning how to ride an epic flying mount may seem to have an astronomically high price, until you find out how much gold you make simply by leveling up. 5000 gold is still a high price, but not nearly as extreme as it would be before the expansion.
Fact is, you’ll make well over 1000 gold just be leveling up from quests and selling random crap you find, and that’s excluding revenue from selling things on the Auction House. Hence, “questing” is present in my little list below.
Questing
By the time you’re 70, chances are you will have a lot of left-over quests in Outland. Seeing that the experience reward of a quest gets converted into gold when you’re the maximum level, you’ll get a lot more out of a quest at 70. Sadly, quests are finite, and the repeatable ones generally don’t offer too much in the way of gold.
Still do the quests you can while they’re available if you need gold. Don’t forget that you’re killing and looting mobs while doing those quests.
Crafting
Crafting has always been popular for making gold, and it looks like things are the same in Outland. Professions of choice would be Alchemist, Enchanter and the new Jewelcrafting.
Potions, enchantments and now gems will be and stay in high demand, and will allow those professions to make good money in the auction house.
Tailors can also fetch a fair buck with the new Spell Threads that can be used to enchant Pants for extra spell damage or healing and stamina. In addition, all tailors can make 18 slot bags with easily obtained ingredients, and Primal Mooncloth specced tailors will be able to create 20 slot bags, I can see a lot of profit being made off those.
Leatherworkers get a bunch of new armor patches with various stats as well as the equivalent of the tailor’s Spell Threads, really sweet armor kits for pants. That sort of thing does well in the Auction House.

Cooking is actually not bad at all at moneymaking too, the various stat enhancing foods are in high demand.
Blacksmiths can make good money selling their highest level droppable gear. The downside is the Primal Nether required by many of them, which is bind on pickup. It’ll take a time investment to get what you need to make the good money as a smith.
Engineering never really was a moneymaking profession, and that didn’t change. There’s a new scope and little fighting robots that can be used by anyone, but that’s about it.
Gathering
Herbalism was a great moneymaker before, and that won’t change.
Mining comes next. With a new profession needing ore and gems, demand is up compared to where it was before. The rare gems especially sell well, as they’re used in some of the nicest jewelcrafting recipes.
Skinning should make good money as well; heavy knothide leather is used in a huge amount of recipes.
Auctioneering
As has always been the case, buying low and selling high can make you good money. Doing this well takes some practice, so I advise you pick one item and monitor its prices for a week or so, and then decide at what price to buy and resell.
Farming
Ahh, the good old slaying of mobs. Motes of various types sell quite well, and they can be gathered in many locations. Another good one is items that are used for repeatable reputation quests. Some examples; Fel Armament, Obsidian Warbeads, Pair of Ivory Tusks and Firewing Signet. A very well selling reputation item is Arcane Tome, which has a very low chance to drop from Blood Elves in Terokkar, Shadowmoon Valley, Netherstorm or the Botanica and The Mechanar in Tempest Keep.