When I graduated from college in 1992 my roommate gave me his schwinn cruiser. I bought a rack and pannier that probably cost a hundred bucks, and cheap lights over the years maybe another hundred bucks. Still has the original tires and chain. I've serviced the bearings a few times but never replaced the balls, so I've got around $200 in cost since 1992. My commuting has been highly variable over the years, but my back-of-the-napkin math estimate is around 7,000 miles on the bike which puts me around 3¢/mile. Rough estimate of total cost of cycling/total miles ridden over the last 10 years is the 50-60¢/mile range, but that includes clothing, food, lodging, travel & event fees. Even a few thousand dollars a year on cycling is so much cheaper than most other hobbies. Heck, my wife's gym membership is $2,500/year.