5 billion $ for R&D cost without nukes.Multiply by three with basic research and nukes R&D for a country with modern high level diversified civilian industry. Then a 3 nuclear warhead ICBM would cost 50 m$ to procure for a twenty year service life plus price of a silo or mobile lauching ramp (add 15 m$ at least) plus 3 m$ a year minimum to maintain and closely to a minimum 4 adding salaries of soldiers to maintain it. In twenty years for a 60 ICBM force it would be 1,2 billion $ a year.This is a little more to the less than 1 billion $ supposed Israelis spending for a 200 nukes and IRBM. This is based on French and US prices. French spend 2,6 to 3 billion $ a year today after reduction of their nuclear aresenal to procure a 4SSBN and 48 SLBM with 288 warheads plus a hundred air launch supersonic counter force 300 kt missiles.

You are both missing the point. How much they cost is not what matters, what matters is how good you are at convincing your bank manager that you need one!!