Short of money, tough at the top perhaps? (4,2)
I believe the answer is:
hard up
'short of money' is the definition.
(I've seen this before)
'tough at the top perhaps?' is the wordplay.
'tough' becomes 'hard' (synonyms).
'at' says to put letters next to each other.
'the top perhaps?' becomes 'up' (I am not sure about this - if you are sure you should believe this answer much more).
'hard'+'up'='HARD-UP'
Can you help me to learn more?
(Other definitions for hard up that I've seen before include "Short of cash" , "Out of funds - it's tough" , "Impecunious" , "Badly-off" , "'In great need (4,2)'" .)