Sounds like a valuable store for the mob (5)
I believe the answer is:
horde
'the mob' is the definition.
(horde can mean a mob or crowd of people)
'sounds like a valuable store' is the wordplay.
'sounds like' shows a homophone (sound like).
'a valuable store' becomes 'hoard' (I've seen this before).
'hoard' sounds like 'HORDE'.
'for' is the link.
(Other definitions for horde that I've seen before include "A mob of people" , "Large crowd" , "Vast crowd" , "Vast multitude" , "Nomadic army" .)