Dashes back to the front to get bargain (4)
I believe the answer is:
snip
'bargain' is the definition.
(slang term for a good deal)
'dashes back to the front' is the wordplay.
'back' says to take the final letters.
'to the front' becomes 'nip' (I can't explain this - if you can you should believe this answer much more).
The last letter of 'dashes' is 's'.
's'+'nip'='SNIP'
'to get' is the link.
(Other definitions for snip that I've seen before include "vasectomy?" , "Cut; bargain (colloq.)" , "Quick cut - something easily done" , "Cut - price bargain" , "Cut with shears" .)