I wasn't too much into the cards. Money is actually very, very pointless in it. The only thing you will ever buy are deeds to the horses, and they all suck except the last 3. You get all the weapons except for like 2 for free during the missions.
Just saving you time if your intention is to get lots of money. Of couse, you can play the card games as you are with money, if that's your thing.