Be deceitful for money, that is (3)
I believe the answer is:
lie
'be deceitful' is the definition.
(I've seen this in another clue)
'money that is' is the wordplay.
'money' becomes 'l' (L can mean 'pounds').
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'l'+'ie'='LIE'
'for' is the link.
(Other definitions for lie that I've seen before include "Assume a horizontal position" , "situation" , "Perversion of the truth" , "Fabrication" , "Be prone - misrepresent the facts" .)