I barter nuts for cheesy snack (7)
I believe the answer is:
rarebit
'cheesy snack' is the definition.
(I've seen this in another clue)
'i barter nuts' is the wordplay.
'nuts' indicates an anagram (nuts can mean crazy).
'i'+'barter'='ibarter'
'ibarter' with letters rearranged gives 'RAREBIT'.
'for' is the link.
(Other definitions for rarebit that I've seen before include "which the Welsh take down?" , "Arbiter of tasty Welsh dish of cheese on toast" , "on Welsh table?" , "See 8 Across" , "Melted cheese with ale on toast" .)