Hawaii on a Budget
Hawaii's climate is similar to what you would find throughout the tropics. There are almost constant trade winds from the east that do keep the temperatures and humidity milder. Summer highs are around 88 degrees Fahrenheit and winter highs are around 83 degrees Fahrenheit. You might find snow at elevations above 13,800 feet on Mauna Kea and Mauna Loa on the "The Big Island".
Sights
The sights in Hawaii are diverse and beautiful. There is natural beauty and hiking opportunities that will impress even the most jaded traveler. There are cultural and historical sights that let you glimpse the unique history that these islands hold tight to. There are also beaches and wildlife viewing opportunities that are unlike anywhere else in the world. Popular sights throughout Hawaii include Pearl Harbor, Diamond Head, the North Shore and Dole Plantation, and Molokini Crater, among many others.Regions
Hawaii is an archipelago that has many distinct volcanic islands, but there are eight major islands with six open to tourists. These six are Hawaii (The Big Island), Oahu, Maui, Kauai, Molokai, and Lanai. Niihau and Kahoolawe are the remaining two islands, the former of which is privately owned and limited to Native Hawaiians and the latter is a former U.S. Navy bombing range.Activities
Hawaii is full of activities that appeal to adventuous outdoor lovers. There are hiking and eco tours available on most islands. There are snorkeling and scuba diving options everywhere as well. Other interesting options include taking helicopter tours over the volcanos, whale watching, or taking surfing lessons. If you're looking for an adventure then any of the islands will have something that appeals to you.Food and Dining
Hawaiian food is a mix of Hawaiian, Portuguese, American and Asian-Pacific flavors. Seafood is abundant and excellent and there is local beef available that comes from Maui. Coffee is typically grown on the Big Island. Popular tropical fruits include pineapple, mango, bananas, guavas, and papaya. If you're on a tight budget, a filling and traditional meal is a plate lunch. It is available at lunch wagons or food courts and typically includes a meat or fish and sides of rice and macaroni salad. Perhaps the most famous Hawaiian dining experience is the luau. This is a traditional Hawaiian feast that involves music, dance and barbecue. Modern luaus that are prepared for tourists are typically buffet style and provide entertainment and delicious food. They are held throughout the islands at resort hotels and some restaurants, but they are expensive, often costing between $50 and $100 a person (half price for children).Transportation
Most international flights to Hawaii pass through Honolulu. Once you're in the state, air travel is the most common and easiest way to travel between islands. It is typically cheapest to make a "triangle route" if you're planning to visit more than one island. This means you arrive and depart from different islands. There are many scheduled flights between islands and it is usually possible to buy tickets a day or two in advance, although prices may be significantly higher if you book last-minute.There are charter boats that travel between some islands as well. This is particularly true in the Maui-Molokai-Lanai area, but crossing the channels between islands can be very rough at times.
On the island of Oahu you'll find a decent public transportation system that travels between Honolulu, Waikiki, Makaha, Schofield Barracks, and elsewhere. The system is referred to as "The Bus" and you should pick up a route schedule from a local ABC Store once you arrive. The other islands offer very limited or no public transportation. They are very rural and a rental car is advised. It's also possible to get a campervan. For the best prices, make a reservation as soon as possible. The rate per day usually goes down the longer you rent the car. Also, check with your hotel to confirm the price for daily parking, if any.
I think what makes Hawaii particularly expensive is that you really need to have a car to explore any of the islands in depth, and rental cars can be expensive.