In the original rules of the game, players had to ante up a random card from their deck every game. There were other cards that added to this ante during the game itself, much like doubling in backgammon. The point was to make the person who went out and spent a lot of money on the deck likely to risk more "monetarily" than the player who only spent a few dollars.
I played this way for many years and I still think it's the best way to play the game, with the trading of cards to get back the ante card a key mechanism to improve one's deck.
