Standard editions of the game will come with one pack, while the digital deluxe edition and retail collector's edition will feature three.
A single pack of Hearthstone cards works out to about $1.49 and features five cards, selected by random, with at least one coming in at Rare quality or higher. If you're particularly lucky you'll pick up an Epic or Legendary card. If you're incredibly lucky you'll get a Ragnaros and everyone on Battle.net will hate you.
How do you get them? Digital editions of the game will deliver the card packs straight into your account, while retail editions will feature redeemable codes in the box. Worst case scenario, it might give you something to do if the Diablo 3 servers collapse
A maximum of five packs can be redeemed to a single Battle.net account, Blizzard adds.
Diablo III: Reaper of Souls will be released on March 25.