Money put into eg West End's opening show? (7)
I believe the answer is:
matinee
'show?' is the definition.
(matinee is a kind of show)
'money put into eg west end's opening' is the wordplay.
'money' becomes 'tin' (old-fashioned slang term for money).
'put into' means one lot of letters goes inside another.
'eg west' becomes 'Mae' (actress Mae West).
'opening' says to take the initial letters.
The initial letter of 'ends' is 'e'.
'tin' placed into 'mae' is 'matine'.
'matine'+'e'='MATINEE'
(Other definitions for matinee that I've seen before include "After lunch, show" , "Play, perhaps" , "sort of jacket" , "Daytime performance of play etc" , "Afternoon theatre" .)