Young fellow, one putting money by, has initially to be welcomed (6)
I believe the answer is:
shaver
'young fellow' is the definition.
(I've seen this in another clue)
'one putting money by has initially to be welcomed' is the wordplay.
'one putting money by' becomes 'saver' (I've seen this before).
'initially' suggests taking the first letters.
'to be welcomed' is an insertion indicator (inserted letters are welcomed in).
The initial letter of 'has' is 'h'.
'saver' enclosing 'h' is 'SHAVER'.
(Other definitions for shaver that I've seen before include "A razor or its user" , "little boy" , "youngster once" , "Electric razor" , "Boy < barber" .)