Commuting by bike saves me about $1000/yr in gas and $3000/yr in parking. My door to door time is not greatly different from driving. I enjoy riding my bike, even more in bad weather, it makes me feel active and alert and alive. It helps keep me fit, although I need to do more for sure. On the flip side, I probably spend $300/yr on tires, tubes, bike maintenance, and the occasional clothing purchase.