Rental Cars

You will want to pick up a rental car at the Kona International Airport (KOA). There are shuttles that will take you to the car rental agencies that are less than a mile away.
After searching various car rental sites today, the two companies that had the best rates were Dollar and Thrifty. On both of their websites, they had "city specials" or "Hot rate discount" that you want to check out.

Dollar: www.dollar.com
One week car rental

Compact - Dodge Caliber $197.25 out the door
Mid-Size - Ford Fusion $216.93 out the door
Full Size - Dodge Charger $226.76 out the door
Mini Van - Dodge Caravan $295.62 out the door
There are 4x4 vehicles or convertibles at a higher prices...

Thrifty: www.thrifty.com
One Week car rental rates
Hot rate discount

The same rates as dollar..

There could be better deals as we get closer to May. In the past I have found coupon codes online that can be entered in at checkout to reduce the rates even more. Also, package deals might also give you a better rate.