Honolulu Airport Shuttles is owned by someone who owns 3 other taxi companies. So they tell you you are getting a good deal as compared to other companies, which they own and offer you "VIP deal" just for you of course.
The prices are rediculous ($80 to go to Pearl Harbour when it costs $2 on the bus) and the owner is the rudest person I have met. They never showed up for one of my tours and I'm $300 out of pocket now.
Unique Suggestions: If you must do a tour, use a legit bus company such as Roberts or Enoa etc rather than a cabbie offering you a special deal. Also, it is easier to book all this once you are in Hawaii and can see the options available to you. "The Bus" is so reliable.
As far as I can tell, it would be cheaper to rent a car for one day than to take a taxi from the airport to a restaurant, and back. To get from the airport to Top of Wakikii, we paid $40 ($3 tip). To get back we paid $36 (included tip).
The taxi meter is based on time. Both trips our elderly drivers went as slow as they could. They slowed down for every light to catch the red. They went below the speed limit on HI while cars whizzed by us on either side. Unbelievable.
A definite tourist trap, since we didn't know the shortest routes. Rent a small car.
Unique Suggestions: Rent a car, avoid taxis.
The other thing that is a tourist trap is the many trolleys. I think I saw Blue, Green and even Rainbow trolleys circulating through Waikiki. We got on one (was free from our breakfast). It was worth what we paid for it. Takes a long time to get anywhere, the bus stops were unclear, and if you were to actually pay for the ride, it was $10 per person per day. Don't bother with the trolleys.
The other associated trap was Hilo Hatties. Somehow the trolleys include Hilo Hattie in their list of stops. Hilo Hattie may be home-grown Hawaiian, but it is an expensive store to buy your souvenirs.
Fun Alternatives: Take The Bus - local transit.
Once you arrive at airport, with bags in hand, you have to figure a way to get to you destination. Taking a cab or shuttle can easily cost over $50 for the ride. Look around the airport, there are free books they give to tourists with coupons for many attractions. In there you can find coupons to call shuttles to take you to your hotel for only $5-7 a person.