Bought from Blacksmith Abasi in Uldum for 80 gold, requiring Exalted with the Ramkahen faction.

Purchased for 165 Tol Barad Commendations from the Hellscream's Reach (Horde) or Baradin's Wardens (Alliance) quartermasters, requiring Exalted reputation.

Standard ground mounts for your faction can be bought from race-specific vendors in major cities (e.g., Stormwind for Alliance, Orgrimmar for Horde) at level 20. Reputation & Currency Vendor Mounts

Sold by Mei Francis in Dalaran for 20,000 gold. This allows for repairing and selling items on the go.