More difficult saving nothing — for this person? (7)
I believe the answer is:
hoarder
'this person?' is the definition.
(hoarder is a kind of person)
'more difficult saving nothing' is the wordplay.
'more difficult' becomes 'harder' ('hard' is associated in meaning with 'difficult').
'saving' is an insertion indicator.
'nothing' becomes 'o' (looks like zero - 0).
'harder' enclosing 'o' is 'HOARDER'.
'for' is the link.
(Other definitions for hoarder that I've seen before include "Person acting like a squirrel" , "Saver" , "Person gathering and storing objects" , "One who accumulates or stockpiles" , "One saves" .)