Lady deer says "Money!" (3)
I believe the answer is:
doe
'lady deer' is the definition.
(I've seen this in another clue)
'says money' is the wordplay.
'says' indicates a 'sounds like' (homophone) clue.
'money' becomes 'dough' (dough can informally mean money).
'dough' is a homophone of 'DOE'.
(Other definitions for doe that I've seen before include "Feminine counterpart of stag" , "partner for a buck" , "Female creature" , "She's a deer" , "Ode to a female deer" .)