Instinct for money in the market (5)
I believe the answer is:
flair
'instinct' is the definition.
(thesaurus)
'money in the market' is the wordplay.
'money' becomes 'l' (L can mean 'pounds').
'in the' is an insertion indicator.
'market' becomes 'fair' (both can mean a place where things are sold).
'l' inserted within 'fair' is 'FLAIR'.
'for' acts as a link.
(Other definitions for flair that I've seen before include "Intuitive discernment" , "Natural talent or panache" , "Taste" , "Bent" , "Faculty" .)