I had dropped 5 foils, the first ones where in shogun 2, in the middle of the summer sale. What was funny is that I dropped 2 consecutive foils, with each one being worth of 1 dollar to me. Then I dropped another one in awesomenauts which didn't sell for that much, but well, at this point 30 cents is better than 7. Then I got the best drop ever, I decided to complete the badge from the summer sale and my last card drop was a tomb raider one, I got 2 dollars for it. And recently I got a foil from guncraft, I got 35 cents for it
I'm amazed that dota 2 foils are still valuable, they are at the 2 dollars range, I would have thought than those would have tanked a long time ago like the one from team fortress