Very little money? Artist needs pounds -- that's key (7)
I believe the answer is:
central
'key' is the definition.
('central' can be a synonym of 'key')
'very little money? artist needs pounds' is the wordplay.
'very little money?' becomes 'cent' (I've seen this in other clues).
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'needs' is a charade indicator (letters next to each other).
'pounds' becomes 'l' (L can represent the monetary pound).
'cent'+'ra'+'l'='CENTRAL'
'that's' acts as a link.
(Other definitions for central that I've seen before include "Most important, principal" , "Near the middle" , "Key" , "Middle; crucial" , "Extremely important" .)