Limit one coupon per account. Regular price $8.35. Out of stock, but Amazon will honor the price when they get more.
Renting a car at one place and dropping it off at another is often very expensive, because the rental companies do not like one-way car rentals.
This blog post lists some options that can save you money:
Availability is very limited, unless you need to drive a well-known path such as Florida-to-New York in the Fall.