What appear to be useless trading cards began appearing in my Steam inventory. Little did I know that I could sell them for money. Which, of course, VALVE takes some of. At any rate, they're pretty much a Steam Wallet Stock Market. Sell them, buy them, and get free games. I bought Booster Troopers, because it was one of the only games that I could afford from just selling City 17 Metrocops.
