In life, expense to be paid (3)
I believe the answer is:
fee
'be paid' is the definition.
I can't tell whether this definition defines the answer.
'in life expense to' is the wordplay.
'in' indicates the answer is hidden within the clue.
'FEE' is hidden within 'life expense to'.
Can you help me to learn more?
(Other definitions for fee that I've seen before include "price" , "Money paid for professional services" , "Amount paid for job" , "Sum payable to, say, barrister" , "Payment to a professional for services" .)