A sound note can mean money (5)
I believe the answer is:
dough
'mean money' is the definition.
'dough' can be an answer for 'money' (dough can informally mean money). I'm not sure about the 'mean' bit.
'a sound note' is the wordplay.
'a sound' indicates a 'sounds like' (homophone) clue.
'note' becomes 'do' (musical note, as in do-re-mi).
'do' is a homophone of 'DOUGH'.
'can' acts as a link.
Can you help me to learn more?
(Other definitions for dough that I've seen before include "Flour and water mix; money" , "Floury mixture" , "Flour mixture for bread and pastry" , "Money (sl.)" , "'Dosh'" .)