Paid for, as agreed upon (7)
I believe the answer is:
settled
'paid' is the definition.
(thesaurus)
'as agreed upon' is the wordplay.
I cannot quite understand how this works, but
'agreed' could be 'set' and 'set' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'for' acts as a link.
Can you help me to learn more?
(Other definitions for settled that I've seen before include "Established" , "no longer an issue" , "Resolved (an argument)" , "Resolved; calm" , "Colonised; decided" .)