Contribution put in exchange (5)
I believe the answer is:
input
'contribution' is the definition.
(input means someone's contribution to something)
'put in exchange' is the wordplay.
'exchange' indicates an anagram.
'put'+'in'='putin'
'putin' is an anagram of 'INPUT'.
(Other definitions for input that I've seen before include "Data entry" , "Data entered to computer" , "Data etc supplied to computer" , "Person's contribution (to a project)" , "Feed data into a computer" .)