The majority of the people on this list have paid vastly inflated prices for islands that were already desirable, or that someone else had at least already built a home on. It was never going to be that way for British survival expert Bear Grylls, who loves a challenge. Grylls paid a mere $150,000 for a tiny, rocky island called St. Tudwal West off the coast of Wales in 2001, and set to work on it alone, turning it from nothing into a fantastic vantage point to survey the local wildlife.
The island already had an old lighthouse cottage, but Grylls has upgraded that to turn it into a unique home from which he can watch dolphins, otters, and seals out in the water. Neighbors on the mainland have only complained once, and that's when he installed a huge metal slide into the side of one of his cliffs in 2015.