^
Umm...what Son of Beast cost- it was millions. A lot of millions. About $20,000,000 exactly, in 2000 terms. Using a inflation calculator, that's $26,866,085.95 in 2012 dollars- Son of Beast was probably, adjusted for inflation, the most expensive thing Kings Island ever built (Diamondback was $22 million, but that was in 2009 dollars, so it's adjusted price is $23,720,728.83 for 2012...less than SOB, and not counting the many fixes/repairs SOB got).
Hmm...out of curiosity, here's what some of Kings Island's other coasters would cost in 2012 dollars...
Racer (Opened: 1972)- $6,640,679.43
Not a bad price, considering the park got two coasters...
Beast (Opened: 1979)- $12,744,738.29
Beast was, for a woodie, pretty expensive...most woodies don't hit the $10M mark (some do, but they seem fairly rare). Then again, they were building the tallest drops and longest track for any wooden coaster in the world at the time...
King Cobra (Opened: 1984, Closed: 2001)- $6,679,027.91
Not a horrible price considering the size of the ride whatsoever...even though its "cheapness" meant it would die an early death.
Vortex (Opened: 1987)- $8,144,964.79
OK- ask B&M to build a 148' tall coaster that goes upside down six times, you'll probably get a price tag of well over $16,000,000+! Seems the rumors that Kings Island got a deal from Arrow on Vortex, due to The Bat's failures, are true...
Adventure Express (Opened: 1991)- $6,793,450.81
OK, wow...I had no idea Adventure Express cost more than King Cobra and rivaled the price tag of Vortex. That theming must not have been cheap...
These are the only prices I could find using rcdb.com and an inflation calculator, converting the cash of the year these rides opened to 2012 dollars...yeah, Paramount was very stingy on sharing how much their coasters cost, apparently...SOB and Diamondback prices are listed way above near the top...
Just more random info I thought might be interesting...oh, Tomb Raider: The Ride was worth $25,716,175.65 in 2012 dollars too, BTW...Kings Island demolished $50,000,000 worth of rides in 2012. Yikes.