Pay for 'mature' film? (7)
I believe the answer is:
footage
'film?' is the definition.
(footage is a kind of film)
'pay for mature' is the wordplay.
'pay for' becomes 'foot' (as in to foot the bill).
'mature' becomes 'age' ('age' can be a synonym of 'mature').
'foot'+'age'='FOOTAGE'
(Other definitions for footage that I've seen before include "Quantity of film (of event)" , "Piece of filmed material" , "Part of film" , "Length of film" , "quantity shot" .)