What do people think of the economic benefit if you keep your car? I would imagine that most of the benefit is not having a monthly payment/insurance.
Yeah I might save a generous 50 cents a mile (That's a total of $5k IF i ride my bike every day for the whole year, more likely $2,500). Add in wear/tear on a nice bike and a couple hundred on tune-ups over the year. I don't think the ~$1,500 benefit is worth the time loss-Hundreds of hours. You basically have to sell your car to get economic benefit from it.
That said, I do love the exercise from it.
You certainly save the most money if you can cut a car out of your life. I was able to put off buying a car for quite a while by riding to work, and the savings were pretty awesome.
I cycle to work two or three times a week at the moment and drive the remaining time. That means that I use about 50% less gas (my car is pretty much only used for commuting), and there's 50% less wear and tear on my car.
Fixing bike problems is pretty easy/cheap and oddly kinda fun, so I do it myself. The gas money alone more than pays for money spent fixing my bike, (and that includes replacing components on my winter bike on an accelerated schedule because of salt damage). If I paid a shop to do repairs, I'd end up spending more money on the bike that it would cost to drive.
My cardio now mostly comes from commuting which ends up saving me time. It takes 40 - 50 minutes to bike to work, 30 - 45 minutes to drive so biking is slightly slower . . . but I get about 3 - 4 hrs of decent cardio intervals each week by biking that I'd otherwise need to make time for. Couple that with a few basement free-weight training sessions a week (and maybe a long ride on weekends) and there's no need to have a gym membership at all so that could save you money.