A lot of the cost of cars aren't obvious to the user, you pay £300 to £600 for a set of new tyres every 12-24 months and you don't add that to the cost per mile of your car (typically 2-6p per mile). Breakdown cover (which can be anything from £30 to £200 for the year, depending on the cover provided) and that's not counted either. Parking charges may only be a few pounds each time, but over a year they all add up. Likewise ask those other things which you may or may not buy like a bit of extra screenwash, car charger, dashcam, satnav, ice scraper, car wash/kit I was your car, new bulb, etc.
It all adds up and many people don't know the true cost of what their car actually costs them over the course of a year.
Even a fairly cheap lease car costing £150 a month is £1,800 before you've even driven it a single mile. In comparison that's nearly as much as a bus pass for a large area in Southern England (£1,860) for two adults which gives you unlimited travel. Even if you buy a £15,000 car and keep it for 15 years that's still more than a single bus pass and chances are as the car gets older your going to have to spend more to keep in going, which will push your annual costs up. Not least as you'll likely need to replace some expensive bits like timing belts, as well as replacing the battery a few times (which can easily be the equivalent of about £40 a year).
All those little things all soon start to add up. A few years ago I worked out that for many people, that they could (excluding fuel and the initial purchase cost) spend somewhere around £750 to £1,000 a year. Add in fuel, parking and purchase costs and it wouldn't be hard to be spending £3,000 a year (with lower milage cheap to buy being closer to towards £2,000 especially in more rural areas where parking is cheaper and there being no upper limit).
At £3,000 a year doing 7,000 miles it's not that different to the 45p a mile which the government allows you to claim tax free as expenses for business travel. Few would ever think that their costs were even as much as 30p a mile. Yet they probably are.