So marginal cost of about 15p a mile?
The extra over the cost of fuel is 15p the full costs, at £2,500/10,000, is 25p a mile, however if you're doing that sort of miles in a year chances are you'll have higher maintenance costs than the £40 MOT charges for each of the following two years.
However I suspect with VED of £300 the fuel efficiency isn't going to be very good, so you'll be paying more than 10p/mile.
As an example a 40mpg car with petrol costing 105p a litter would be 12p/mile, if petrol goes back to pre lockdown prices of 130p then that rises to 15p/mile. That's then 30p/mile.
Conversely at 3,000 miles it's 50p a mile (10p/mile fuel cost).
The point being, and nothing anyone has said so far disproves it, that cars are often more expensive than people expect.
Even doing 10,000 miles a year with £100/year depression (OK a fairly high, but not crazy high instance and VED don't help the case, but even if they were lower but depression was £400/year which is still fairly low) and assuming very optimistic maintenance costs it still ended up at £2,500 a year (possibly more depending on fuel efficiency).
As such but that far off the average I've quoted of over £3,000.
Whilst doing less miles does being the cost down, the cost then isn't good value due to the cost per mile going up a LOT.
As for lease car chargers, it's fairly easy to find leases (and they will likely be limited to 6,000 or 8,000 miles before incurring extra charges) of £200/month. If you get one and leave it on your land and don't drive it or insure it that's £2,400 a year for something that looks nice.
Even with free fuel (let's say it's electric and you can charge it off your solar panels, although even that would likely have a cost associated with it) as well as servicing, VED and insurance included, at 8,000 miles that's still 30p a mile.
In reality it doesn't take a lot of extra charges for those costs to rise significantly..
Even where people don't pay parking very often it's still fairly easy for those charges to add up.
There's also other little things, such as you get the car serviced, that's miles which you are still paying for but aren't benefiting from.
You drive a mile (say) to school because it's a bit overcast and you don't want to get wet, that's still a cost which if you were doing a lot of miles by train wouldn't cost you anything as you'd walk.
You do a long journey and come off at a motorway services, you can easily added another few miles, again distances which aren't needed in your travel.
I fully understand the convince of a car, and how it allows you to do things which wouldn't be possible without it. It still boils down to the fact that often it is costing people a lot more than they think.
As for it costs me X to do this trip or that trip, unless you are doing them regularly then the high costs aren't changing your overall travel costs all that much. If you are doing it regularly then those journeys are subsiding the user of your car the rest of the time by significantly increasing your milage.
However, as has been pointed out, it might be better to hire a car for those trips and use other modes for the rest of your travel.
Likewise, comparing the cost of train travel for one stop on a train on a turn up and go ticket is always likely to show up anomalies. As to go 10 times that distance may only be 3 times the price.
That would be like comparing the cost of road travel by looking at the cost of driving all the miles in a year as if it was crossing the Thames at Dartford and ignoring the fact that whilst someone may do that fairly frequently there's a whole load of other traveling that they undertake at other times.
However even at £20 return, if a car costs £2,000 a year you could still undertake that trip twice a week for the same cost, much more than that and you may well find that a season ticket works out cheaper.
Whilst there's going to be rail/bus journeys which are impractical by anything other than car because of the layout of the networks (be that railway lines or bus routes) that's always going to be the case whilst cars are the default mode of choice.
As if public transport and cycling rates increased then there would be more routes provided, the more routes provided the easier it is for now people to use them, meaning that more routes were provided.
Unfortunately the opposite is true (and this is often where we are at), people use buses/trains/cycles infrequently, so no investment is made, meaning that it's not viable, so fewer people use them, etc.
To give you an idea of how bad things are; we'd all expect there to be less cycling undertaken than in 1950, few would have a problem with that. Traffic is worse, we can afford to run cars more easily, we have more stuff which we buy so have to carry in a car, etc.
However on the otherwise if the coin or bikes can be much lighter (and I'm thinking of £400 bikes, not the carbon fiber cost as much as a car bikes), have much better gears (can even have assistant in the form of e-bikes), there's many more long distance cycle routes, and so on and so forth. As such cycling in many ways should be easier.
Yet to get to 1/2 the average distance per person (total miles traveled divided by total population) we'd need to increase cycling by a factor of 2.4.
Why? It because so many people haven't used a bike in years (quite possibly haven't opened a bike since they were a kid), not even for a few trips a year which could easily be undertaken by bike when they aren't likely to get wet. This then means that their kids don't see cycling as a normal thing to do and so don't do it.
Kids are trained from a young age that the only way to get about is by car, as that's the way they always go to school, is to go by car. Now I understand that many have a long way to go to school, however the vast majority don't. Often the time saving from going by car isn't that much, however the cost of doing so is likely to be high.
Not necessarily in terms of money (although I'd a second car is being run almost for the sole purpose of school transport it will be) but rather in terms of how healthy the children are, in terms of pollution, in terms of disruption caused by traffic, in terms of the number of parked cars taking up space and so on.
Actually, if there were fewer cars on the roads were could remove some parking from urban areas and replace it with vegetation. This could include the planting of trees on terraced streets where there's few plants visible, with the benefits of a nicer place to live, the reduction in pollution created by the trees, an increase in wildlife habitat and a reduction in temperature during the summer by reducing solar gain by creating shade. It would also reduce flooding downstream and could also improve the quality of the storm water which does run into the sewers.
That's just one area where if we want to avoid significant problems with climate change then car ownership patterns need to change rather than just everyone switching to EV's. In the greater scheme of things they aren't that great, just look up about the impact that the mining of the minerals has on the planet.
Even just on motive emissions EV's are worse than trains. That's ALL trains, not just EMU's. The emotions per passenger per 10,000 miles for EV is 0.60 tonnes, with the potential to green the grid to improve this.
Conversely, rail, including diesel trains, when averaged over the same per person per 10,000 miles from national figures results in a figure of 0.59 tonnes, the the potential to green the grid, change to bimodal/battery/hydrogen trains, electrify more lines.
As such, and given that we're aiming for net zero, even the small difference that there currently is going to help us get closer (read not having to pay as much for carbon offsetting/carbon capture) than would be the case of we carry on using cars.
Of course even in writing the above is not a fair comparison, in that someone doing 10,000 in a car if they switched to doing the same travel by train would almost certainly not do the same miles in a year as they'll reduce their travel and walk for some of there travel.
