Youngster holds search, not the first, for reward (6)
I believe the answer is:
bounty
'for reward' is the definition.
(bounty is a kind of reward)
'youngster holds search not the' is the wordplay.
'youngster' becomes 'boy' (I've seen this in another clue).
'holds' is an insertion indicator.
'search not' becomes 'un' (I can't justify this - if you can you should give a lot more credence to this answer).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'un'+'t'='unt'
'boy' placed around 'unt' is 'BOUNTY'.
'first' is the link.
Can you help me to learn more?
(Other definitions for bounty that I've seen before include "Present" , "blood money" , "Christian vessel" , "Generous gift" , "Abundance" .)