Maybe money that's left on account, last of salary (6)
I believe the answer is:
legacy
'maybe money that's left' is the definition.
(money left in someone's will)
'on account last of salary' is the wordplay.
'on' becomes 'leg' (cricket term, fielding positions).
'account' becomes 'ac' (abbreviation).
'last of' suggests the final letters.
The final letter of 'salary' is 'y'.
'leg'+'ac'+'y'='LEGACY'
(Other definitions for legacy that I've seen before include "Something handed down" , "Like old software" , "A bequest, something left in a will" , "Birthright" , "Willed gift" .)