Coin boxes mainly sold without money (9)
I believe the answer is:
insolvent
'without money' is the definition.
'coin boxes mainly sold' is the wordplay.
'coin' becomes 'invent' (I've seen this before).
'boxes' means one lot of letters goes inside another (the outside letters must 'box' inside letters in).
'mainly' means to remove the last letter.
'sold' with its final letter taken off is 'sol'.
'invent' placed around 'sol' is 'INSOLVENT'.
(Other definitions for insolvent that I've seen before include "strapped for cash" , "Snivel not, although you are bankrupt!" , "Unable to pay debts owed" , "In the red" , "deep in debt?" .)