Commuting by bike doesn't save me any money. However, it does defray the cost of my cycling hobby.

Commuting by bike doesn't really save time. My drive is 20 minutes and my bike is 45 minutes. However, it does save me time if you consider that when I get home, I don't feel the need to go for an hour ride or disappear on my bike for 2 or 3 hours on weekends.