Cash raised for public school (4)
I believe the answer is:
eton
'public school' is the definition.
(Eton College)
'cash raised' is the wordplay.
'cash' becomes 'note' (I've seen this before).
'raised' says the letters should be written in reverse (going up in a down clue).
'note' reversed gives 'ETON'.
'for' is the link.
(Other definitions for eton that I've seen before include "old school" , "Famous English public school" , "Posh British public school" , "collar, perhaps?" , "Berkshire public school" .)