Sale item consisting of large books (3)
I believe the answer is:
lot
'sale item' is the definition.
(I've seen this before)
'large books' is the wordplay.
'large' becomes 'l'.
'books' becomes 'ot' (Old Testament).
'l'+'ot'='LOT'
'consisting of' is the link.
(Other definitions for lot that I've seen before include "Genesis character" , "His Biblical wife was turned to a pillar of salt" , "part of France?" , "one whose wife was backward-looking?" , "Piece of ground" .)