The Steam Trading Cards Beta currently states:
What about free to play games like Team Fortress 2 or Dota 2?
Free to play games drop game cards based on your in-game purchasing. For every $9 USD spent (approximate) since the start of the Steam Trading Card Beta, you will earn one card drop. This card will drop at some point as you play. If you have made in-game purchases in Dota 2 or Team Fortress 2 prior to the Steam Trading Card Beta, or if you owned Team Fortress 2 prior to the Free to Play update, you will have 4 or 5 additional card drops available.
While it only mentions in-game purchases, will buying items from the Mann Co. Online Store count as an "in-game" purchase? I more often use the the Mann Co. Online Store when buying things; I can easily switch tabs to the Wiki and see each item's detail, and that helps me when buying any item.
Essentially, if I purchased $9.00 USD of items from the Mann Co. Online Store, will I get a trading card, or must all purchases be completed via the in-game store?