Expensive for the time, 1958, the most of any car manufacturer, the Cadillac Brougham

$13,074... for the 1958 Cadillac Brougham. $2000 more than the Rolls Royce that year (Hot Rod Deluxe May 2008, Page 42)
From a feature on this car http://www.johndagostinokustomkars.com/images/58%20Cadillac%20Eldorado%20Brougham%20Kustom%206.jpg