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]
(..) well its not true ok, im a classy broad yeah i can see that umm, listen, speaking of classy chow bellas a really expensive restaurant so we can go anywhere else tomorrow. i really dont care as long as were together are you kidding me? no, years we've been going out... (..)2012 Ted