You'll be brought into our raid for Heroic Madness only, receive both the title "Savior of Azeroth" as well as the mount.
The expected price is 100k, but may change depending on availability.
There are now only 3 weeks remaining to get this mount with 100% guarantee. This has been confirmed by blue posts.
9th Sep - Available
12th Sep - Booked
19th Sep - Available
Message Brahmann in-game if you're interested.