Must have been a short-lived promo. It currently has a $24.99 price tag.

Edit: Yep, it was free for 24-hours.

http://steamcommunity.com/games/397060/announcements/detail/868452655740947781

Looks like I missed it.

I missed that too :S:

It is now permanently free.

Pretty fun game. Only played a few matches, but I already like it better than Hearthstone. Building the board as you go and moving your units around as you play makes for a very interesting play. It's not just down to the luck of the draw.

I was waiting for this one for a while, since I casually like computer card games and there were like no multiplayer ones on Linux. Ironclad Tactics is technically a card game, but it doesn't match the gameplay style like Solforge and Hearthstone and Magic.
Do I like Faeria more than Hearthstone? I can't answer that yet. But I can say that I can easily shelve Hearthstone as another game I don't need to boot into Windows for. (Last time I booted Windows was 32 days ago.) Hearthstone is a good, fun game, but Faeria is also fun, to the extent that I don't think I'll miss Hearthstone.

Quoting: 14I can easily shelve Hearthstone as another game I don't need to boot into Windows for.

Hearthstone runs really well in Wine.