Raised money used at first for single item (4)
I believe the answer is:
unit
'single item' is the definition.
(I've seen this before)
'raised money used at first' is the wordplay.
'raised' says the letters should be written in reverse (going up in a down clue).
'money' becomes 'tin' (old-fashioned slang term for money).
'used at' is a charade indicator (letters next to each other).
'first' becomes 'u' (I can't justify this - if you can you should give a lot more credence to this answer).
'tin'+'u'='tinu'
'tinu' reversed gives 'UNIT'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for unit that I've seen before include "Single manufactured item; military grouping" , "Army division" , "1 entity" , "One; military group" , "army group" .)