I don't have a clue about World of Warcraft but am going to assume this is a expansion pack?
Anyhow I noticed this is £11.50 @ Tesco. Free click and collect or free 5 day delivery. Had a quick look to see if it's any cheaper anywhere else. Amazon is the next cheapest at £22.99.
The Collector’s Edition of Mists of Pandaria includes the full version of the game on DVD-ROM and contains the following exclusive bonus and in-game items:
World of Warcraft In-Game Mount: Take to the skies of Azeroth astride the mystical Imperial Quilen flying mount.
World of Warcraft In-Game Pet: Journey across Pandaria with the Lucky Quilen Cub at your side.
StarCraft II Battle.net Portraits: Bring the Horde and Alliance rivalry to the far reaches of the Koprulu sector with exclusive Infested Orc and Night Elf Templar Battle.net portraits.
Diablo III Banner Sigil and Accent: Display your status as a hero of Pandaria with the iconic markings of World of Warcraft’s newest playable race, the pandaren.
Behind-the-Scenes DVD and Blu-Ray: Learn about the creation of Pandaria with this two-disc set featuring over an hour of commentary, insider interviews, and developer roundtables.
Collector’s Edition Soundtrack CD: Experience 20 orchestral pieces from Mists of Pandaria.
The Art of Mists of Pandaria Book: Explore this 208-page hardcover tome featuring never-before-seen pieces from the expansion, from early concepts to final 3D renderings.
Chen Stormstout Mouse Pad: Equip your desk with this special-edition mouse pad featuring the legendary pandaren brewmaster.