Young men following game wasted a lot of money (9)
I believe the answer is:
megabucks
'a lot of money' is the definition.
'young men following game wasted' is the wordplay.
'young men' becomes 'bucks' (I've seen this before).
'following' is a charade indicator (letters next to each other).
'wasted' is an anagram indicator.
'game' anagrammed gives 'mega'.
'bucks' put after 'mega' is 'MEGABUCKS'.
(Other definitions for megabucks that I've seen before include "Vast sums of money" , "A fortune!" , "large sum of money" , "Many grand" , "Loads of money" .)