Coins used by heir (5)
I believe the answer is:
scion
'heir' is the definition.
(I've seen this in another clue)
'coins used' is the wordplay.
'used' is an anagram indicator.
'coins' is an anagram of 'SCION'.
'by' acts as a link.
(Other definitions for scion that I've seen before include "Young family member" , "Young twig; descendant" , "Plant shoot; descendant of a noble family;" , "Younger member of a family" , "Branch" .)