Game is second sale item not won (5)
I believe the answer is:
lotto
'game' is the definition.
(lotto is a kind of game)
'second sale item not won' is the wordplay.
'second sale' becomes 'lot' (I am not sure about this - if you are sure you should believe this answer much more).
'item' becomes 'two' (I've seen this before).
'not' suggests deleting specific letters.
'won' becomes 'w' (I've seen this in other clues).
'two' with 'w' taken away is 'to'.
'lot'+'to'='LOTTO'
'is' acts as a link.
(Other definitions for lotto that I've seen before include "Bingo - Venetian painter" , "Bingo-like game" , "Housey-housey, bingo" , "Children's game, housey-housey" , "Game in which numbers are drawn" .)