The ones that haven’t been developed will need something done for power and water which is costly.
You need a generator/solar,build a desalination plant, large dock. But it doable.
The ones that have already been setup for living on are real expensive.
Here’s some
$500k to $50 million.
We know some people who bought an island in the 1980s near Green Turtle Cay. They built a house and have been living in it full time for 30 years. It’s truly paradise. We visited with them this year when we were in the Bahamas. They have a 10,000 gallon cistern for rain water, solar panels/generator setup. Mango, coconut, and some kind of banana like trees. Big raised gardens. Chickens. Pretty well self sufficient. They’re less than five miles from a small town.