Blizzard would like you to spend a further £4 on Hearthstone, and to be honest we may be too weak-willed to argue.
For your money you'll get 10 packs from the game's classic card set and a guaranteed top-level legendary minion.
The offer will most benefit newbie players, especially as the classic card set will never lose value - the game's annual cycle of filtering out older sets does not affect the classic set, which will always form the basis of the game.
It's of less use to players who likely have all the regular classic cards already, and most of the classic legendaries.
There's no way of knowing which legendary you'll get, although the list is drawn up from the various class-specific legendary minions in the classic selection - such as Grommash Hellscream for the Warrior and King Krush for Hunter.
You can only get the bundle once, too - reinforcing the fact it's a one-time deal and an obvious first purchase for those just starting.
One thing experienced players should note is that several classic Hearthstone cards are now banned from the game's arena mode for being too prevalent.
For everything else Hearthstone, head over to guides site Metabomb.