About band from the ’90s making comeback: one only works for money (4)
I believe the answer is:
merc
'one only works for money' is the definition.
(mercenary)
'about band from the '90s making comeback' is the wordplay.
'about' becomes 'c' (abbreviation for 'circa').
'band from the '90s' becomes 'rem'.
'making comeback' shows that the letters should be reversed in order.
'c'+'rem'='crem'
'crem' back-to-front is 'MERC'.
(Other definitions for merc that I've seen before include "business-class car" , "one hired for foreign work" , "High-performance German car" , "German make of luxury car (colloq.)" , "Former cop" .)