I couldn't possibly care less. I would ride my bike if someone were giving me car and gas for free.
It's actually pretty cheap for me to drive, compared to what most folks around here say. I do almost all my own car wrenching. I have a 12 year old car with 128K miles on it. It was $18K new, I pay about $600/year in insurance, and I've put $1600 total since new into all repairs and consumables to date (2 new sets of good tires, wipers, oil and filter changes, etc, plus lately I've had to take it to the shop and have them do some deeper engine work that I just didn't have the time to do myself).
Ironically, the deep engine work were both sludge related, and that was almost certainly caused by the fact that I hardly ever drive the thing anymore. A car that gets driven 10 miles 2 times a week winds up getting all sludged up because the water never gets burned out of the crankcase.
So in that respect, bike commuting has increased my car expenses. But I've saved more than that in gas.
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Work: the 8 hours that separates bike rides.