Insurance charge is a bonus (7)
I believe the answer is:
premium
I believe this clue is a double definition.
'insurance charge' is the first definition.
(I've seen this before)
'bonus' is the second definition.
(I know that premium is a type of bonus)
'is a' is the link.
(Other definitions for premium that I've seen before include "Sum paid for insurance" , "cash needed for cover charge" , "Amount payable for insurance etc" , "Additional cost" , "Great value - bonus" .)