$7,053,533,987.5 Cost Per Plane in Silver Inflation Adjusted Dollars.
$19,764,715,982.14 Cost Per Plane Gold Inflation Adjusted Dollars.
The Blackbird was a Billion Dollar Plane! The F-22 Raptor's 339 million dollar price tag seems almost reasonable in comparison to the 1960's $543,968,750 cost of the Blackbird. In CPI inflation adjusted dollars the Blackbird was over ten times the price of the Raptor. The Blackbird's successor the Aurora must have had a staggering price tag as well.
Update 17 January 2016
I believe that the cancellation of this program had something to do with the assassination of JFK. He was set to go after the contractors that worked on the ANP. They were looking at prison time. The Blackbird, if it had been used as planned as a bomber, would have changed the game in Vietnam as well. It is unlikely there would have been a Hanoi Hilton full of American pilots, if A-12's were doing the bulk of the bombing.
Dewar, James A. To the End of the Solar System: The Story of the Nuclear Rocket. Lexington, Ky.: U of Kentucky, 2004. Print.
Pluto 700 Million and $5 Billion [1961 dollars] for 240 ramjets Dewar 65.