Go away with stuff after start of sales (5)
I believe the answer is:
scram
'go away' is the definition.
(scramming is a kind of going away)
'stuff after start of sales' is the wordplay.
'stuff' becomes 'cram' (cramming is a kind of stuffing).
'after' means one lot of letters go next to another.
'start of sales' becomes 's' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'cram' put after 's' is 'SCRAM'.
'with' is the link.
(Other definitions for scram that I've seen before include "Clear off!" , "Make oneself scarce" , "beat hasty retreat" , "Vamoose" , "In slang, go away and beat it" .)