The Reins of the Drake of the South Wind drop from Al'Akir in the Throne of the Four Winds on both Normal and Heroic modes. It can also be listed on the Black Market Auction House.
Here you can buy Drake of the South Wind for EU or US Servers.
You'll get guide for getting Drake of the South Wind
You'll be able to get Drake of the South Wind
Drake of the South Wind mount
Additional budget for Character transfer or Character boost to max level. BMAH Services in Shadowlands now requirement to have a max level character on server, so Trial character will not work.
Free time on evening, if you choose selfplay option