Ok so if you read any gold blogs or guides, you might know about Truegold in 4.2
It is supposed to skyrocket in price because it will be used in so many more recipes come the new patch. Keep in mind this is speculation, and does not guarantee anything.
Vial of the Sands requires 12 Truegold, and as of now, at least on my server the prices vary between 35k-40k. With truegold becoming more expensive... so will the mount. If you have the money to invest, it could be a well worth payoff.
tldr; buy lots of truegold and vial of the sands