Perfect boy saving sum of money (4,2)
I believe the answer is:
spot on
'perfect' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for spot on that I've seen before include "Exactly right" , "Excellent" , "what soiled garment had?" , "Precisely what's required" , "Precise" .)