The problem with this as gamification is that there is zero ability to play for less than the current high-score. That is a real problem: suppose 500 people were wiling to pay close to, but not over, $10, but hardly anyone was willing to pay over $10. If 15 people have paid $10 it now prices anyone wanting to pay up to $10 completely out of visibility. Since we said there were 500 such people, you lose $5,000 while making 15 * 10 = $150. That's a real design problem. Pay-to-play should give everyone something.