Proper to put notes next to coin (6)
I believe the answer is:
decent
'proper' is the definition.
(associated in meaning)
'notes next to coin' is the wordplay.
'notes' becomes 'de' (two musical notes).
'next to' says to put letters next to each other.
'coin' becomes 'cent' (cent is a kind of coin).
'de'+'cent'='DECENT'
'to put' is the link.
(Other definitions for decent that I've seen before include "Proper; passable" , "Modest and respectable" , "Obliging or modest" , "Upright" , "Modest or kind" .)