A SINGLE cow is what it cost Jack to buy the beans that grew into a giant stalk, but the King of Swaziland has had to trade considerably more beef on the hoof for his own latest acquisition: a bulletproof, air-conditioned luxury car. King Mswati III is the world's last absolute monarch and a man who rarely has to explain himself, least of all to the poverty-stricken subjects of his tiny landlocked mountain kingdom wedged on the eastern border of South Africa. He felt obliged last week, however, to issue a statement explaining that he had not plundered taxpayers' money to buy himself one of the world's most expensive cars, but had traded his own cows for the plush ride. The king is used to brushing off the many critics who complain he spends too much on himself and too little on his people. The recent acquisition of a $US500,000 ($630,000) Daimler Chrysler Maybach 62 sedan, though, has sparked much anger and controversy. Along with the Maybach, Mswati also bought 10 5-series BMWs — a Valentine's Day gift for each of his 10 wives. The king's habitual generosity to his spouses, and himself, at the expense of the national treasury has prompted international condemnation and threats to cut off aid to Swaziland. He has tried to buy himself a multi-million-dollar jet aircraft and recently spent millions more building palaces for each of his wives, to the outrage of opposition groups and donors.