Can you tell me where you got that number?
According to USAF docs, the cost is about 150M per jet (for USAF versions). For the entire support systems that go along with it, and weapons, the total cost per unit is about 192M (http://www.saffm.hq.af.mil/shared/media/document/AFD-110211-038.pdf, pg 57 of 560).
I am not that familiar with USMC/Navy budget docs, so a link would be good.
Thanks.
Since they nixed the alternate engine supplier, you can bet that over the next 10-15 years the engine prices will go up and power improvements will be small.
FY 2012 Program Acquisition Costs by Weapon System:
http://comptroller.defense.gov/defbudget/fy2012/FY2012_Weapons.pdf
Page: I-7 ($6,644M for 32 aircraft = $207.6M