guppy44: Seems odd to run out of freebies. Since there are a set number of games for sale before the promo ends it would appear they planned to run out? Or perhaps it's more likely they didn't expect so many users reaching the freebie goals, what with more expensive titles this sale and all.
It seems they did know that this might happen according to their FAQ:
How do I unlock free games?
You'll earn free games while making purchases during the sale. Your first free game is unlocked after purchasing 10 games. From that point on, the number of purchases required will go down with every game you unlock.For example: after these 10 initial purchases and your first freebie, you will need to buy 9 more games to unlock your second free game, 8 for the third, 7 for the fourth and so on until you receive one free game for every 5 purchases.When you purchase a bundle with multiple games, each one will count towards your next free game.
Keep in mind that the stock of free games is limited. However unlikely, it's possible they may run out. Additionally, only games that are part of the Insomnia Sale lineup count towards your total.