Sunfleet Car Sharing is a Swedish company that lets you rent their cars for just as long, or short as you want. I got to use one of their cars for free as I drove up to see a real estate development I have been part of. They gave me a car and I made them a video. See it below:
Super smooth company to work with and really easy to use. Sign up online, download their app, book a car and go drive! Gas is paid for by the company and you are billed for the time and distance.