GMG is having a deal which you can get a mystery game (limit to just 1 per account) at just 6 cents (AU 8 cents, using 28 deg card).
People have replied that they got games such as American Truck Simulator and COD BlackOps. I've got Jack Zero, Bridge Constructor and Shattered Haven myself and surprisingly while my Steam account is having 1000+ games I've got none of those yet.
Might not be a great bargain but it's fun regardless; and for 8 cents it's not a big deal if you get a bad game.
I placed the order and it took my money but my cart is showing a message that says:
Sorry - We have temporarily run out of keys. We are expecting more keys soon. We will send you a separate email with your key once we receive additional stock.