I always like to have at least $200 in my wallet. Usually any purchase over $20 goes on my credit card anyway. I got stuck once when my car was towed in Manhattan. They had no ATM at the place and did not take credit cards. I had to walk a mile each way to get to an ATM. I heard the story a while back about someone who got robbed at gunpoint at a 7/11 and only had $1 on them. That can be dangerous too, because I've heard stories of people getting killed because they did not have enough money on them. I think people who leave less that $20 in their wallet at all times are foolish.