Once again I hesitate to put my head into the buzz saw that is this thread, however....
Without getting into great arguments about 2008 $ vs 2002 DM, etc, surely the cost of purchasing an aircraft is actually fairly irrelevant for the nation buying it, what matters is the overall costs of ownership over the life of the fleet (I don't want to argue about $ per flight hour either).
I once visited a UK aircraft manufacturer and was told that they made almost no money on selling an aircraft, where they made their money was in the costs they charged for supporting it over the next 25-30 years. It's not inconceivable that a manufacturer/nation would actually sell their aircraft at a loss, simply to achieve the sale and the long term follow on support.
I certainly remember reading many years ago that the French, in the days of the Mirage III, virtually gave the aircraft away, but then charged an arm and a leg to support it.....
I'll get back in my box now.....