My commute is 65 miles each way. I drive 7 miles to a commuter rail station, and take my bike in the train and ride five miles to work.

Cost of driving the full distance by car =~ $30 per day (my calc. based on my actual usage, not AAA's higher catch all $.50/mile calc)

Rail pass=307/mo = $15/day
Cost of driving 14 miles =$3.50/day
money spent biking per year =1500, = $6.00/day

Yes, it cost less, not even counting the intangible benefit of being a cure for freeway burnout, and just plain fun.