Man on public transport performing for money (7)
I believe the answer is:
busking
'performing for money' is the definition.
(to busk is to play music for money in public)
'man on public transport' is the wordplay.
'man' becomes 'king' (man can mean a chess piece).
'on' says to put letters next to each other.
'public transport' becomes 'bus' (bus is a kind of public transport).
'king' put after 'bus' is 'BUSKING'.
(Other definitions for busking that I've seen before include "Playing street music" , "Serenading passers-by" , "performing for donations" , "Performing in the street for money" , "street diversion" .)