Sale to the highest bidder (7)
I believe the answer is:
auction
'sale to the highest bidder' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for auction that I've seen before include "Caution about method of sale" , "Offer to bidders" , "event with lots involved" , "Use caution at public sale" , "A lot will be seen in this" .)