A lot of money for piece of music (7)
I believe the answer is:
fortune
'a lot of money' is the definition.
(I've seen this before)
'for piece of music' is the wordplay.
'piece of music' becomes 'tune' (a tune is a piece of music).
'for'+'tune'='FORTUNE'
(Other definitions for fortune that I've seen before include "large sum of money" , "Great accumulation of wealth" , "Providence" , "Fate, destiny" , "Fate; riches" .)