After credit money's not all there (8)
I believe the answer is:
crackers
'not all there' is the definition.
(both can mean insane)
'after credit money's' is the wordplay.
'after' is a charade indicator (letters next to each other).
'credit' becomes 'cr' (abbreviation).
'money's' becomes 'ackers' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'cr' put next to 'ackers' is 'CRACKERS'.
Can you help me to learn more?
(Other definitions for crackers that I've seen before include "Nutty - biscuits" , "they may be on the table at Christmas" , "nuts and > bananas" , "Crazy types" , "Mad - fireworks" .)