If I were to give up my car I'd roughly save an average of $1,100 annually. On the other hand, living in the rural northeast, it's only practical to ride from April-November (I have no problem riding 50 miles /day in fair weather conditions), and cabs are ridiculously expensive. During the off-peak season (winter), I researched taking a cab a round trip to/from work(25miles one way) would cost me $13,680 and a once-a-week round trip to the grocery store(10 miles one way) would cost me $1,056 plus the lack of freedom I would have if I drove or biked.
Of course biking has it's additional benefits; no gym memberships, only one wellness check up each year and no prescription co-pays. Bike parts are usually cheaper in most retrospect, although common bike parts often wear faster then their auto counterpart in my experience and can come out even over time/harsh conditions.