M: I need 100 black pens and 200 blue ones. W: What do you need so many pens for? Are you planning to write a book? M: Very funny. I need them to pass out at the electronics conference we’re hosting next week. W: Oh, yes. I’ve seen the signs advertising that conference. I hear it usually draws a large crowd. M: Yes, it’s a popular event W: Let’s see… at 40 cents each, the total for your pens comes out to $120. Will that be cash or charge?