for me personally I save no money by commuting. very rough number crunching here: to drive my car costs $0.16/mile ($3/gal fuel, oil change, tires) excluding cost of car and insurance because I have those regardless. maintenance on my bike costs $0.12/mile (just tires and tubes). that's a difference of $.04 cents a mile. so to break even on my $800 bike would take 20,000 miles of commuting. only way I see to save money by commuting is by having no car, a cheap bike, or a terribly non-fuel efficient vehicle. does that mean i'm selling my bike? of course not, I do it for the love (exercise ain't bad either).