Deanna, for this question I've decided to go right to the source, and get some ideas from Daisy at Hawaii Travel Guide:
Hawaii rental cars are the best – and often only – way of seeing the islands at ground level.
Unless you want to ride the city bus – available only in Honolulu – or spend your vacation crammed like a sardine into a tour-can with 50 other people, rental cars are the way to go while vacationing in Hawaii.
Each island offers special treats for drivers. From the (in)famous Hana Road, on Maui, to Oahu’s Na Pali Highway, spectacular waterfalls and breathtaking vistas await drivers in panorama mode. For the most part, driving in Hawaii is easy and convenient for dining and engaging in special excursions. Conversely, many areas – like the entire island of Kauai where secluded waterfalls reveal themselves only to the adventurous – are rural and virtually inaccessible without transportation. (Special note: Many waterfalls are seasonal in Hawaii; so visits during the rainier winter months will yield better results for those who want to make this a key part of their trip.)
Once you’ve decided to go ahead with it, fear not, cheap Hawaii car rental is not out of the question. Affordable deals can be made because there is extensive competition on the islands – especially among the larger brands on Oahu. Additionally, several simple things can be done to trim rental car costs.
One of the best ways to reduce the cost of Hawaii rental cars is to book well in advance. Many companies offer bundle-type deals if airfare, hotel and rental car transactions are conducted together.
When purchasing Hawaii rental cars, it will be tempting to reserve a vehicle for a single day to test drive the experience before committing further. And that may be a good plan for some. However, longer term reservations equal smaller daily costs. There is also a secondary benefit in that a rental car will be available. Rental agencies do regularly sell out in Hawaii, especially during the summer high season.
Rental companies will also frequently push its own insurance. But it is usually expensive, so decline it if possible. In many cases, the individual’s personal insurance already covers rental cars. That makes the rental company’s coverage redundant and, therefore, an unnecessary expense.
Don’t forget fuel costs when adding up anticipated expenses. Fuel costs, if not checked, can also add significantly. Hawaii has some of the highest priced gasoline in the entire country, so it makes sense to forgo a large, gas guzzling rental. Instead, opt for a fuel efficient model that will get the job done at a fraction of the cost.
Finally, don’t pay to have the rental company refill the vehicle’s gas tank for you. Use a gas station near the airport to save a bit of cash.
Remember, every dollar saved is a dollar to spend on the many activities uniquely available in Polynesian. With the savings from these simple tips, get a spectacular new perspective on the landscape you’ve been exploring with one of the many Hawaii helicopter tours available on each of the islands.
Thanks Daisy... some great tips for Hawaii rental cars! Deanna, I hope you find a great deal on a discount car rental in Hawaii.