How much stuff should I bring?
Well the less you bring the better. Hawaii has a tropical climate so a lot of your clothes and furniture might not be made for this climate. Moving to Hawaii meant for many of us to get rid of a lot of stuff.
For example leather sofas do not hold up very well in some of the more humid areas, there are certain materials that work much better here. In terms of clothes, well - it all depends on where you going to live. In general you only need board shorts, T-shirts a light sweater or jacket and maybe a pair of pants - island life is simple. You can legally drive barefoot and even go to the supermarket without a shirt on.
TIP: Be aware though that there is not a really great selection on furniture and interior design products as you might be used to from the mainland, but you can just check some of the stores online to see what they got.
Cars: If you plan to bring your car with you when you are moving to Hawaii, expect a fee of about $1000 for a standard car to ship it by freighter.
Plants: There are very strict plant quarantine restrictions in place if you want to bring plants into Hawaii. Those restrictions are to protect the crops in Hawaii and to not introduce bugs and diseases into our environment and agriculture. There is beautiful plants here and they are usually very easy to grow - There are also some nurseries on the mainland, which have a clearance to ship to Hawaii. Here is more info regarding importing plants to Hawaii.
Animals: If you want to bring some animals with you when you are moving to Hawaii, make sure you know about Hawaii's restrictions for bringing in pets. Those regulations are designed to protect Hawaii from the spreading of rabies. The import requirements are regulated by the so-called 5-day-or-less program, which includes rabies vaccination, microchip implant, rabies blood test etc. Some non-domestic dogs and cats are prohibited to enter the state at all. Here is more info regarding importing of cats and dogs to Hawaii.
There is also regulations for other animals like livestock, poultry, birds, insects, reptiles and fishes. Here is more info about importing animals to Hawaii.
Cost of Living: Unless you are living off the grid, your power comes to large degree from power generators, which are powered by oil. That means high electricity costs, when the oil prices are up. Hawaii is trying to set up alternative power stations up until 2030 to produce 70% of Hawaii's needed energy, but for now it is quite pricey. Same of course for prices at the pump.
House prices totally depend on the island and area. If you don't mind paying top dollar, you can move to Oahu, Maui and Kauai. If you want affordable Hawaii living Puna on the Big Island has still really good and low-cost real estate.
Food is more expensive than in the rest of the US. This is because we are dependend on importing goods from the mainland and elsewhere and because many of us still rather eat mainland apples than local grown fruit.
Keep your budget down by live in a low-cost area like Puna, grow your own food or buy at local farmers markets and think of switching to solar power. This will make moving to Hawaii a great experience.