Like some bought items with quiet salesman to help (7)
I believe the answer is:
prepaid
'like some bought items' is the definition.
(an item which has been bought might be prepaid)
'with quiet salesman to help' is the wordplay.
'with' says to put letters next to each other.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'salesman' becomes 'rep' (I've seen this before).
'to help' becomes 'aid' ('aid' can be a synonym of 'help').
'p' next to 'rep' is 'prep'.
'prep'+'aid'='PREPAID'
(Other definitions for prepaid that I've seen before include "settled in advance" , "Settled early" .)