Reasonable ticket price for audience (4)
I believe the answer is:
fair
'reasonable' is the definition.
(I know that reasonable can be written as fair)
'ticket price for audience' is the wordplay.
'ticket price' becomes 'fare' (I've seen this before).
'for audience' indicates a 'sounds like' (homophone) clue.
'fare' sounds like 'FAIR'.
(Other definitions for fair that I've seen before include "Exhibition of commercial or industrial goods" , "Equitable ? - trade show" , "Blonde; beautiful" , "Average" , "square" .)