Display cut including promotional item (6)
I believe the answer is:
parade
'display' is the definition.
(parade is a kind of display)
'cut including promotional item' is the wordplay.
'cut' becomes 'pare' (paring is a kind of cutting).
'including' means one lot of letters goes inside another.
'promotional item' becomes 'ad' (advert).
'pare' placed around 'ad' is 'PARADE'.
(Other definitions for parade that I've seen before include "March-past of troops etc." , "Organised procession of displays, performances, etc" , "Exhibit" , "Assembly of troops for inspection" , "Flaunt; ceremonial march" .)