The economists who wrote about how societies developed the money
system, were not in touch with any historians or anthropologists who
were then making first contact with indigenous people in Americas,
Africa, Asia, Austalia. They didn't bother checking with any of them.
They had no clue about how it actually came around. They merely
speculated, with their understanding of humanity limited to the urban
western humanity that they grew up around.
So the simplistic origins of money that we "know", that are taught in
textbooks and upon which our economic understandings are based .. are
stories created in some people's heads. Not reality. What the
historians and anthropologists have found is extremely different.
Some things emerging from what the historical and anthropological records tell:
Money system did not naturally evolve from barter system. Barter did
not precede money.. it succeeded it where the money-issuing mechanisms
went defunct. Credit systems (ie, keeping accounts of who owes whom
how much) did not succeed money.. they preceded it.
And "gift" economy system, where credit is informalized and made
non-binding and rather left to ethical compulsions and occasionally
forgiven as well as overpaid as per circumstances, seems to have
preceded them all, existing wherever there wasn't a centralized
bureacracy levying taxes/tributes, as well as in parallel with the
other systems as a more day-to-day system of local exchange whereas
money/credit was a periodic once-a-year or one-time-investment types
thing for most of humanity until very recently.
So it's entirely possible that the typical assumptions we have about
people in a village getting confounded with how to exchange eggs,
woodwork, grains and all.. it's possible that that typical story that
we impose onto their lives are merely a reflection of our own flawed,
simplistic and linear understanding of history and humanity.
Two sources that might shine further light in this direction:
http://www.unwelcomeguests.net/Debt,_The_First_5000_Years (David Graeber, 2011)
http://charleseisenstein.net/ (Sacred Economics and other books)
Please put in some time to looking them up.. there are plenty of
related audio/video versions too that you can listen to comfortably.
Also, there is a collaboratively created and open-sourced alternative
economics syllabus made and released recently by a network of people
who saw the mainstream syllabus of most top-level economic colleges as
woefully out of date. I've read only the first few pages and it's been
amazing so far. Their tagline is "Teaching economics as if the last
three decades had happened".