Secure item of neckwear reduced in price (3,4)
I believe the answer is:
tie down
'secure' is the definition.
(thesaurus)
'item of neckwear reduced in price' is the wordplay.
'item of neckwear' becomes 'tie' (I've seen this before).
'reduced in price' becomes 'down' (knocked down in price).
'tie'+'down'='TIE DOWN'
(Other definitions for tie down that I've seen before include "Bind by conditions - to widen (anag)" , "Restrain with ropes" , "Fix; bind by conditions" , "Restrict" .)