Zipcar currently charges per hour to rent a vehicle from its fleet for a short time. The company is also testing pay-per-mile pricing in a few US cities, but there's no indication as to whether or not the new structure will be widely available in the future. As The Verge explains, the pilot program is actually a combination of the two pricing methods. You can rent a Honda Fit in Chicago for $4.50 an hour during the week or $5.50 an hour on the weekends, both of which tack on an additional 50 cents per mile. With regular pricing, a Nissan Versa costs $10.75/hour on a weekday with a 180-mile allotment before extra fees kick in.