Sale where caution is exercised (7)
I believe the answer is:
auction
'sale' is the definition.
(public sale)
'caution is exercised' is the wordplay.
'is exercised' indicates an anagram.
'caution' anagrammed gives 'AUCTION'.
'where' is the link.
(Other definitions for auction that I've seen before include "Offer to bidders" , "Lots are sold here!" , "event with lots involved" , "A lot will be seen in this" , "Public sale - type of bridge" .)