"I won the contest." See, easy and free. I'd say, price of card +20% should be enough. So Hilbert can give one extra to someone else who participated in contest. 20% is not for his pocket. It would be fee to display your name alongside real winners while putting next to it following text: (sponsored) And then this extra fee would serve as way to give some nice memory sticks/SSD or something in one extra contest.