Reduced-price event (4)
I believe the answer is:
sale
'reduced-price event' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sale that I've seen before include "See 12 Down" , "Transaction" , "Occasion for buying at reduced prices" , "Auction; Cheshire town" , "Auction - somewhere in Greater Manchester" .)