Finally! It looks like the cat is finally out of the bag, here are the Curse of Naxxramas Pricing Details:
After the Arachnid Quarter, the next four wings can be purchased for 700 gold per wing or $6.99 per wing. Players can earn the in-game gold needed to unlock the next wing of Naxxramas by completing various quests or emerging victorious from the Arena, or they can choose to unlock the next available Naxxramas wing using real money.
You’ll want to make sure to take advantage of that first free wing, because it’s for a limited time only!
Players who begin their adventures in Naxxramas during the launch event will gain free access to the first wing: the Arachnid Quarter. The launch event will last roughly a month or so, meaning you’ll have plenty of time to get your foot in the door—we’ll have more details to share about that later on. The web-choked corridors of the Arachnid Quarter are home to the bosses Anub’Rekhan, Grand Widow Faerlina, and Maexxna. Defeating these bosses will add new cards to your collection and give you a taste of the dangers that await you deeper inside Naxxramas.
If you want to buy in bulk, here are the prices:
- All five wings: $24.99
- Already own first wing (purchase remaining four): $19.99
- Already own first two wings (purchase remaining three): $14.99
- Already own first three wings (purchase remaining two): $9.99

What this means is that you’ll be able to buy a wing with gold, one with real money, and buy the rest in a bundle. You can mix and match these circumstances to fit your ability to pay!
If you unlock additional wings with gold and wish to purchase a wing bundle at a later time with real money to unlock any remaining wings, you can still take advantage of the bundle pricing. For example, if you enter the Arachnid Quarter during the launch event and unlock it for free, then purchase the second wing with gold, the remaining three wings can be purchased with real money at the 3-wing bundle price listed above.
Heroic Mode Details
Heroic mode leads to a new card back, it seems you’ll have to craft the golden version of cards to obtain them.
Once you’ve defeated all of the bosses within any given wing for the first time, you’ll unlock the Heroic mode of that wing. Heroic mode bosses are significantly more difficult than their normal versions, and they will prove to be a challenge for even the most veteran Hearthstone players. Defeating all of the bosses in Naxxramas on Heroic mode will unlock a new card back for your collection.