not sure about the coupon price but I returned a car 10 day early- I had rented it for 2 months and didn't need those last 10 days so brought it back early. I didn't get a penalty or anything but I still paid for the whole 2 month rental which I had figured I would anyway since I prepaid it and got a great rate- less than 2,000 for a minivan for 2 months (I put 11,000 miles on that van in less than 2 months!)