The car's in for MOT tomorrow so I've just updated our spreadsheet of bills, fuel and mileage. Makes for interesting reading.
Averaged over four years it works out at a fixed annual cost of £1300, plus 9p per mile, plus fuel (around 13p / mile).
For our mileage it means if we preferred to hire cars or take taxis, our monthly budget for that would be a hefty £270. (Needless to say, SWMBO convinced that taxi / hire car combo is not suitable).
More interestingly, it transpires that the marginal cost of driving to work is £3.04 per day, essentially the same as getting the bus, except that the bus takes around 1.5 hours per day longer (equivalent to almost double my annual leave allowance).
Since we both (mostly) ride to work, we save on all the costs of the second car we don't own (£1300 fixed + 220 x £3 = £660 -> ~£2k) plus the marginal costs for the first we don't commute with (220 x £3 = £660).
Over ten years to date that's £25k cash. I'm almost certain we haven't spent that much on bikes... scary really.