The money we raised for a nut (6)
I believe the answer is:
cashew
'a nut' is the definition.
(cashew is a kind of nut)
'the money we raised' is the wordplay.
'the money' becomes 'cash' (I've seen this before).
'raised' shows that the letters should be reversed in order.
'we' in reverse letter order is 'ew'.
'cash'+'ew'='CASHEW'
'for' is the link.
(Other definitions for cashew that I've seen before include "Kind of nut" , "Kidney-shaped nut of tropical tree" , "snack perhaps" , "Acajou" , "nut-tree" .)