``Power couple Jay-Z and Beyoncé took out a conventional mortgage to help finance their new Bel Air spec mansion -- amounting to an unconventional $52.8 million. The amount equates to 30 years of monthly payments at $252,075, based on an interest rate of 4 percent, the Los Angeles Times reported... The couple, through blind trusts, paid $88 million total for their 30,000-square-foot compound...''