Put back small-change coin (8)
I believe the answer is:
tuppence
'coin' is the definition.
(tuppence is a kind of coin)
'put back small-change' is the wordplay.
'back' says the letters should be written in reverse.
'small change' becomes 'pence' (I've seen this before).
'put' back-to-front is 'tup'.
'tup'+'pence'='TUPPENCE'
(Other definitions for tuppence that I've seen before include "small cost" , "''Feed the birds, .... a bag'' (Mary Poppins)" .)