I am a big fan of ‘History of Yesterday’ but sadly in this case I believe you are mistaken. Barter economies are a backup often when the larger state has collapsed but they were not according to many historians ever a long term arrangement. Conceptually many believe that a favour or credit system was in place: https://www.google.co.uk/amp/www.inquiriesjournal.com/amp/1396/implausible-barter-narrative-in-ancient-babylon

As a source of history I recommend watching out for these sorts of myths.