If anyone wants to buy packs, now is the time. Using Amazon's in-game 'Coins', I was just able to purchase 147 packs for $80. That's $0.54/pack, compared to $1.25/pack if you buy Blizzard's largest package in-game.
Unsure if it's a promo glitch or what, but here's the process. Note that you MUST use the Amazon app store version of the game. If you don't have a tablet that can run it, you can download
DuOSand download/purchase packs from there.
1.
Purchase10,000 Amazon Coins (Using either 5 or 10k options on the Amazon site). This will cost $80.
2. Each time you then buy bulk packs in game (15 or 40 packs), you get a refund of 50% of the coins spent. For instance - 40 packs costs 5000 coins, but after you purchase you instantly receive 2500 coins back into your account. You receive 1000 coins back on a 15 pack purchase (normal cost is 2000 coins).
3. To get max value, purchase 2-40 packs, 4-15 packs, and a 7 pack. This yields you 147 packs and leaves you with 0 coins.
Math for those interested:
Credit to r/hearthstone for the initial find on this. It also seems to be NA only, but I can't confirm.