Just transport charge, it's said (4)
I believe the answer is:
fair
'just' is the definition.
('fair' is associated in meaning with 'just')
'transport charge it's said' is the wordplay.
'transport charge' becomes 'fare' (I've seen this before).
'it's said' indicates a 'sounds like' (homophone) clue.
'fare' is a homophone of 'FAIR'.
(Other definitions for fair that I've seen before include "(Of skin) pale" , "Equitable, just (4)" , "here for the ride?" , "Just; fete" , "honest" .)