Set price being fixed, proceeds (8)
I believe the answer is:
receipts
'proceeds' is the definition.
(thesaurus)
'set price being fixed' is the wordplay.
'being fixed' indicates anagramming the letters.
'set'+'price'='setprice'
'setprice' is an anagram of 'RECEIPTS'.
(Other definitions for receipts that I've seen before include "Income, takings" , "Notes acknowledging money paid" , "Cooking instructions once" , "Acknowledgments of monies paid" , "Acknowledgments of payment" .)