Book bargains here, and manuscript, item to be auctioned (6,3)
I believe the answer is:
salems lot
'book' is the definition.
(novel by Stephen King)
'bargains here and manuscript item to be auctioned' is the wordplay.
'bargains here' becomes 'sale' (a sale offers bargains).
'and' is a charade indicator (letters next to each other).
'manuscript' becomes 'ms' (abbreviation for manuscript).
'item to be auctioned' becomes 'lot' (a lot is an item for sale at an auction).
'sale'+'ms'+'lot'='SALEMS LOT'
(Other definitions for salems lot that I've seen before include "Also smelt (anag) -- novel by 22 14" , "Horror novel" .)