I broke even a long time ago. I'm riding about 6000 miles / year that I would otherwise drive. That's about $960 in fuel I'm not spending every year at current pricing. Considering oil, depreciation and just the various expensive other stuff (tires, shocks, breakdowns) that mileage contributes too and I'm far ahead.

There is a lot more to riding than saving money, but once you have ridden enough to offset the initial outlay (bike, fenders, panniers, lights) the savings add up.

Bike maintenance seems to be lower once you get established. I go thorugh tires once a year ($50), a patch kit every year or so ($5), a chain and cog set every three years ($50/3) and a new NiMH for the light every three years ($100/3).