Cost: $18,500,000

Former Phillies legend Lenny Dykstra bought Wayne Gretzky's custom designed home for just north of $18M, which would be fine and dandy if he wasn't orchestrating a financial fraud. Dykstra's prowess as a business guru is exaggerated with falsified financial statements that are exposed when he falls behind on his enormous mortgage. He's currently serving a three-year prison sentence for grand theft auto and recently plead guilty to bankruptcy fraud. Moral of the story: don't buy a 13,000 square foot mansion when you're broke.