Ticket price sounds reasonable (4)
I believe the answer is:
fare
'ticket price' is the definition.
(eg a bus fare)
'sounds reasonable' is the wordplay.
'sounds' indicates a 'sounds like' (homophone) clue.
'reasonable' becomes 'fair' (associated in meaning).
'fair' is a homophone of 'FARE'.
(Other definitions for fare that I've seen before include "Payment for journey" , "Cost of travel" , "Grip (of a tyre)" , "Taxi charge; food" , "Transport charge" .)