Wheeler-dealer’s stage performance? Flipping rubbish! (8)
I believe the answer is:
operator
'wheeler-dealer's' is the definition.
(shrewd or manipulative person)
'stage performance? flipping rubbish' is the wordplay.
'stage performance?' becomes 'opera'.
'flipping' says the letters should be written backwards.
'rubbish' becomes 'rot' (I've seen this before).
'rot' back-to-front is 'tor'.
'opera'+'tor'='OPERATOR'
(Other definitions for operator that I've seen before include "Director or controlller of machinery" , "Manipulative type of person" , "Driver" , "Poor rate (anag.)" , "Speculator" .)