You can run a car for peanuts nowadays if you don't do a huge mileage.
Just buy something low mileage, 'bland' but well maintained like an old Jetta someone has given full dealer servicing.
Do your own basic servicing and brakes and use eBay for a set of wheels with better tyres when you need 'em.
Use a back street garage with a good reputation.
Try and drive like you were painting a landscape.
Anything major goes, sell it as it stands and go find another bargain.
Use it as little as you need to, but enough to make it pay.
Try never to drive alone, find people who need to get to the supermarket now and then or into town and make it a paying deal.
I am trying to get down to a half dozen vehicles, when I make London my main base again I will just keep a van and a four wheel drive. We can only have two cars in London for our parking, so I am going to have to work out some proper off road parking somehow.