[happinesswithoutpeace]

http://en.wikipedia.org/wiki/Iron_Dome

[Lonesome in Massachussets]

Iron Dome has been criticized for its prohibitive cost. The estimated cost of the Tamir intercept missile is $35,000–$50,000,[5] whereas a crudely manufactured Qassam rocket does not cost more than a few hundred dollars.

Does not sound "cost effective at the margins".