1 general:: Phrase(s): big bucks a very large amount of money. • He earns big bucks for doing almost nothing.
McGrawhill's American Idioms And Phrasal Verbs
2 general:: A great deal of money, as in A swimming pool? that means you're spending big bucks. Buck has been slang for "dollar" since the mid-1800s. [Slang; second half of 1900s]
American Heritage Idioms