Green with no well -- financial resources needed (7)
I believe the answer is:
economy
'financial resources needed' is the definition.
(economising is a way of saving money)
'green with no well' is the wordplay.
'green' becomes 'eco' (abbreviation for ecological).
'with' says to put letters next to each other.
'well' becomes 'my' (I've seen this in other clues).
'eco'+'no'+'my'='ECONOMY'
(Other definitions for economy that I've seen before include "being frugal" , "Financial prudence" , "A country's system of production, distribution and consumption" , "Me coy? No! (anag)" , "Country's financial state" .)