Amazon is currently selling World of Warcraft: Cataclysm for only $19.99 (that’s 50% off the list price of $39.99).

Note, this deal is valid through Saturday, June 16, 2011, until 11:59pm PST, while supplies last.

From the product page:

– Requires the full version of World of Warcraft, Burning Crusade, Wrath of the Lich King, and a Battle.net Account to play.
– Level Cap Increased to 85
– Classic Zones Remade and New High-Level Zones
– Two New Playable Races – Goblins and Worgen
– Flying Mounts in Azeroth

An ancient evil lies dormant within Deepholm, the domain of earth in the Elemental Plane. Hidden away in a secluded sanctuary, the corrupted Dragon Aspect Deathwing has waited, recovering from the wounds of his last battle against Azeroth and biding his time until he can reforge the world in molten fire. Soon, Deathwing the Destroyer will return to Azeroth, and his eruption from Deepholm will sunder the world, leaving a festering wound across the continents. As the Horde and Alliance race to the epicenter of the cataclysm, the kingdoms of Azeroth will witness seismic shifts in power, the kindling of a war of the elements, and the emergence of unlikely heroes who will rise up to protect their scarred and broken world from utter devastation.