Collector's opening bid for chest (6)
I believe the answer is:
coffer
'chest' is the definition.
(coffer is a kind of chest)
'collector's opening bid' is the wordplay.
'opening' suggests taking the first letters.
'bid' becomes 'offer' ('offer' can be a synonym of 'bid').
The initial letter of 'collectors' is 'c'.
'c'+'offer'='COFFER'
'for' acts as a link.
(Other definitions for coffer that I've seen before include "safe" , "Treasury - chest for valuables" , "Strong box at the treasury" , "Treasure chest" , "Chest for storing valuables" .)