Get on with a paying passenger (4)
I believe the answer is:
fare
I believe this is a double definition.
'get on' is the first definition.
(thesaurus)
'a paying passenger' is the second definition.
(I've seen this before)
'with' is the link.
(Other definitions for fare that I've seen before include "Food provided in fear" , "Food, or price of bus ticket" , "Taxi hire cost" , "Get on - passenger - provisions" , "Menu" .)