It is an achievement reward. In the Other Items category. Added in World of Warcraft: Mists of Pandaria. Always up to date with the latest patch.
Bulging Sack of Gold is an item from World of Warcraft: Cataclysm. In the Other Items category. Always up to date with the latest patch.
For those people planning to spend all their garrison resources on the Smuggled Sack of Gold before the prepatch, this macro command will.