Her decision to leave the company proved to be an 'expensive' mistake. [=a mistake that caused her to lose a lot of money]
They live in an 'expensive' neighborhood. [=a neighborhood in which houses, apartments, etc., cost a lot to buy or rent]
an 'expensive' shop [=a shop that sells expensive things]
(..) export military equipment. We have a special Act which subsidizes, makes it possible for countries abroad to buy our armaments because it's too expensive to produce them for one country only. So we have become a very efficient military-industrial complex but the civilian economy is only a ghost (..)2009 Loose Change 9/11: An American Coup