Market again before the end (6)
I believe the answer is:
retail
'market' is the definition.
(I've seen this in another clue)
'again before the end' is the wordplay.
'again' becomes 're' (prefix meaning 'again').
'before' is a charade indicator (letters next to each other).
'the end' becomes 'tail' (tail is a kind of end).
're'+'tail'='RETAIL'
(Other definitions for retail that I've seen before include "A litre (anag)" , "The trade serving the public" , "Sell in small quantities" , "Shopwork" , "Sale of goods to customers" .)