I recall reading somewhere. Maybe, Bicycling Mag. that it costs no more than 1/2 cent to ride a bike a mile, where a car is like .40 cents(minus insurance).
My oldest road bike has over 60,000 miles on it.. A '94 Scott model 520. I have changed both rims(complete wheel sets ) 3 times. A new rim costs (Velocities) costs about $100. I have totally replaced the drive train once(minus the front crank). Put on one set of STI index shifters. About $100.
Routine maintenance like cables, tires, tubes, brake pads, chains ;that is pretty inconsequential. Drive train probably about $250. Headset once. About $30.
If you are not handy or don't take the time to maintain your bike , I suggest you have an annual tune up. $25-75, depending on how complicated an overhaul you want..
That does not include the re-lacing job I had to have done after British Air beat the hell out of my spokes and handlebars.
Over 60.000 miles on my oldest bike. Rides great. Bet that is under 1/2 cent a mile.
Saving on costs. stock up ahead. Like I recommend Armadillo Tires by Specialized..Full price you pay like $39. look for sales and stock up for the next replacement. Seems on sale I have gotten them for $23.