I've been saving up money for some time now with my Horde characters, and got over 1000 gold, because I'm afraid that the flying mounts from the Burning Crusade will cost a lot. The idea was to skip the epic mount, because moving at 200% speed instead at 160% speed isn't worth that much money, and I would rather have gone straight from normal mount to flying mount. Unfortunately Blizzard didn't want to allow that.
Patch 1.12.1, which was introduced this week, changes the system how riding works. Mounts, normal and epic ones, are now very cheap 10 gold and 100 gold respectively, minus 10% for being honored and another minus 10% for having sergeant rank. But to ride a normal mount you now need apprentice skill in riding (75), which costs 90 gold to learn. And to ride an epic mount you need journeyman skill (150) in riding, which costs 900 gold to learn. It seems bloody obvious that riding a flying mount will need expert skill (225) in riding, and cost even more. Plus you can't get the riding skill for flying mounts without having bought the riding skill for epic mounts. You need to learn epic mount riding now, and as the actual epic mount is then comparatively cheap, you can't save much money by not buying it.
I'm sure the gold sellers of World of Warcraft are dancing in the street for joy. As the flying mount isn't "optional" like the epic mount used to be, and you now need to learn riding the epic mount before getting the flying mount, every level 70 player needs to spend a huge amount of cash. Some will farm that for themselves, the others will pay somebody to farm for them. And Blizzard does everything to encourage this farming by bad game design.