Discuss terms say on new set of books I took in (9)
I believe the answer is:
negotiate
'discuss terms' is the definition.
(I've seen this in another clue)
'say on new set of books i took in' is the wordplay.
'say' becomes 'eg' (both can mean 'for example').
'on' means one lot of letters go next to another.
'new' becomes 'n' (abbreviation as in New Testament NT).
'set of books' becomes 'OT' (abbreviation for the Old Testament).
'took in' becomes 'ate' (take in can mean to eat).
'eg' put after 'n' is 'neg'.
'neg'+'ot'+'i'+'ate'='NEGOTIATE'
(Other definitions for negotiate that I've seen before include "treat! Yes!" , "Find a way over (a difficult path)" , "as diplomat does" , "Deal, bargain" , "Pass round" .)