A hiding place for money, say (5)
I believe the answer is:
cache
'a hiding place' is the definition.
(I've seen this before)
'money say' is the wordplay.
'money' becomes 'cash' (cash is a type of money).
'say' shows a homophone (sound like).
'cash' is a homophone of 'CACHE'.
'for' is the link.
(Other definitions for cache that I've seen before include "Hidden store of things" , "Put away" , "Hiding place for treasure etc" , "Treasury" , "Hiding place for treasure or store" .)