Money's not right for singer (4)
I believe the answer is:
bass
'singer' is the definition.
(bass is a kind of singer)
'money's not right for' is the wordplay.
'money' becomes 'brass' (I've seen this before).
'not' indicates named letters should be taken away.
'right for' becomes 'r' (I've seen this in other clues).
'brass' with 'r' taken away is 'BASS'.
(Other definitions for bass that I've seen before include "Low singer" , "Large fish - singer" , "Low-pitched; a fish" , "Very low - perch" , "Fish for the low-voiced" .)