Old bridge for sale (7)
I believe the answer is:
auction
This might be a double definition.
'old bridge' is the first definition.
'auction' can be an answer for 'bridge' (auction is a kind of bridge). I am not certain of the 'old' bit.
'sale' is the second definition.
(I've seen this before)
'for' acts as a link.
Can you help me to learn more?
(Other definitions for auction that I've seen before include "Competitive sale" , "Lots are sold here!" , "Occasion of lots under the gavel" , "Public sale by bid" , "Caution about method of sale" .)