It's not JUST garrisons that made money so inflated, though it helped push numbers from hundreds of thousands into millions easily, it's just the scaling. At every stage of the game gold increases just due to inflation and necessity to make new players/returning players not be at a complete loss to catch up.
For example, in vanilla 1,000 gold was a lot (this is what an epic mount used to cost). Many players didn't even have epic mounts because of it. hyper Rich players might've had ~10,000 gold after 2 years of farming and buying/selling smartly on the ah. TBC gold inflates, now your average player probably had 10-20,000 gold after the expansion (Again, 2 years of farming and playing), and hyper rich players probably had in the hundreds. It just goes on like this, if the gold didn't increase exponentially with each expansion we'd still have new and returning players feeling like farming 1000 gold was a huge feat, but we'd have gold barons with like a million + gold even in vanilla terms.
The result for someone like you is that as you hit each new level cap from previous expansions and move on to new ones, your gold gains are just going to keep skyrocketing. By the time you hit max level you'll easily have 20-30,000 gold just from questing. With a new expansion coming around the corner if you want to keep playing it's an excellent time to make money just by gathering and selling shit or what have you in Legion (assuming you catch up before the rush is over). Once you ahve gold, it starts to feel easy to keep earning it honestly, that's how so many people that post here or otherwise are 'hardcore' about the game manage to pay their subs with tokens, which sit like 45k each right now. There's an initial hump of learning to earn, but it doesn't actually take much playtime to do so once you know how. If you ever start raiding, you're set for life - people pay wayway too much to get carried through raids. One month of sales will pay for a year of gametime easily.
Oh, and regarding mounts: The easiest weird looking one you can get is probably like a Hearthsteed, just win 3 games of hearthstone or something. Otherwise just keep levelling and try to figure out what you want.
