Darling goes after bargain a bit (7)
I believe the answer is:
snippet
'a bit' is the definition.
(I've seen this before)
'darling goes after bargain' is the wordplay.
'darling' becomes 'pet' (synonyms).
'goes after' is a charade indicator (letters next to each other).
'bargain' becomes 'snip' (slang term for a good deal).
'pet' after 'snip' is 'SNIPPET'.
(Other definitions for snippet that I've seen before include "piece of information" , "Bit (of info?)" , "Small scrap" , "piece from the paper" , "Fair --, knitwear style" .)