Cost of going to hawaii?

i am currently stationed in honolulu, hawaii. Personally i would not recommend maui as there isnt much out there on that island. The 2 best island for vacation would be kauwai and oahu ( honolulu / waikiki). The cost living in hawaii is more expensive that most major cities in the US versus NY and San Francisco, CA. $7.00 for a gallon of milk, and 4.35 for a gallon of gas! Hawaii in general is a beautiful place to visit but can be very costly. Hotel (3-4 stars) normally run about $120 a night. Money for cabs run fairly high as a 20 min ride can cost you $45. There a lots to do on these 2 islands IE- sky diving, deep sea diving/snorkling, jet skiing, mainly water sports as you are on an island haha. You can take helicopter tours that take you around the island to get wonderful views of the mountains and waterfalls etc. But maui is mainly boring if you ask me.