Last of the big spenders (3)
I believe the answer is:
end
'last' is the definition.
(I know that last can be written as end)
'of the big spenders' is the wordplay.
'of' says the answer is hidden in the clue.
'END' is hidden in the letters of 'big spenders'.
(Other definitions for end that I've seen before include "Culmination" , "Finish; goal" , "Extreme" , "Finish, wind up" , "Conclusion, finish" .)