I am no great moneymaker ingame by any means, I don't AH pharm, I don't buy gold, I don't pharm for gold for hours a day. I simply send all my sellable goods to my bank alt who in turn posts those goods and gears on the AH.
My warrior did mannage to buy his lvl40 mount at lvl 38 (back when the price of the mount itself was the hefty portion), in addition to a full set of lvl40 plate mail and a new lvl40 two-handed axe (before I got the whirlwind axe from the warrior quest).
Now I'm saving up for the epic mount, with a bit less saved up with only 3 lvls left to go. I'm helping a guildmate make arcanite bars for some quest he has, and I spent a large portion of my bank on arcane crystals that I intended to make into arcanite bars to sell.
The lvl40 mount is chicken feed, the epic mount is a bit more to swallow though.