Good buzzer's entertaining new sound (7)
I believe the answer is:
benefit
'good' is the definition.
(I know that benefit is a type of good)
'buzzer's entertaining new sound' is the wordplay.
'buzzer' becomes 'bee' (insect which buzzes).
'entertaining' indicates putting letters inside (inviting in, as for dinner).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'sound' becomes 'fit' (associated in meaning).
'bee' placed around 'n' is 'bene'.
'bene'+'fit'='BENEFIT'
(Other definitions for benefit that I've seen before include "Avail" , "Advantage or blessing" , "Financial assistance" , "(Gain) advantage" , "Advantage; dole" .)