In terms of material cost, for me it's probably no more than about $100/year. My yearly costs are as follows: lube ($10), new chain ($15), new tires and tubes ($60). This leaves about $15 for misc costs that might emerge.
There are times when it will cost more than $100. Last year I had my rear wheel rebuilt ($160), and sometimes you will need new parts (I've had my bike about 5 years and have replaced the rear derailleur and cassette). So overall, the average annual operating costs are for me are probably around $120 - some years slightly more, some slightly less. Still way cheaper than a car
