My minimum order is one dozen ($54.00) and I deliver free in town (San Francisco) if I have time, or ask clients to meet me to pick up at my local Starbuck's (!!!) if I'm too busy for delivery. As I'm getting busier and have less and less time for deliveries, I have been asking more clients to meet me there, and they have been happy to do so - no problem at all. I charge $15.00 to deliver to Marin (across the GG Bridge about 20 minutes) which works well on 2 fronts: the high-end clientele there love the home delivery (it's a very easy sell), and I get a mini-vacation enjoying the drive and having coffee in a sunny outdoor cafe with a friend before heading back to work. When it comes to downtown San Francisco (I do many company logos) if they won't send a messenger I charge $20 because of traffic/parking issues.
You really have to consider your time or as Julia said, you'll quickly become a delivery service.