If you need to buy something new to save gas, I think the Honda Civic hatchback (or whatever it's called), that has a small four cylinder with a water cooled turbo is hard to beat. A friend of mine bought one a year or so ago as his retirement car and he loves it. It has plenty of power and he just averaged 47 mpg driving from here to Illinois and back. I don't think EVs are ready for primetime yet so if I was buying new, with fuel efficiency in mind, the Honda turbo is what I would get. I don't think it would pollute much more than an EV.
This is what the exhaust pipe on an EV looks like.