The most expensive home for sale in the United States just hit the market for $250 million. At 38,000 square feet, the Bel Air mansion includes 12 bedrooms, 21 baths, a $200,000 built-in candy wall, $30 million in cars and the helicopter from '80s TV show 'Airwolf.' “It’s the best of the best,” says Bruce Makowsky, the hotshot developer who constructed the palatial pad,