Careful thought given to payment (13)
I believe the answer is:
consideration
I believe this clue is a double definition.
'careful thought' is the first definition.
(I've seen this before)
'to payment' is the second definition.
(thesaurus)
'given' is the link.
(Other definitions for consideration that I've seen before include "A motive" , "Thoughtfulness - relevant factor" , "Kindness" , "factor to be borne in mind" , "examination" .)