Thrifty - Anything cheaper than $72 at Kona King Ham hotel location Aug. 29?

We have a cruise stop at Kona, Hawaii on Aug. 29/2012. Trying to rent a car from the Thrifty location at the Kona King Kam Marriott hotel (by the cruise terminal) for that day. But the cheapest rate is coming up as $72.

Tried to use Corp code HT14004118 many people recommended for Hawaii, but no change. Tried other codes but they are invalid for the location/date. Anyone know of codes that can bring the price down? Right now just trying to get the cheapest car.

Thanks.