From an intriguing interview with David Graeber, author of Debt:  The First 5,000 Years, regarding the history of money and debt:

Yes there’s a standard story we’re all taught…  It really deserves no other introduction: according to this theory all transactions were by barter. “Tell you what, I’ll give you twenty chickens for that cow.” Or three arrow-heads for that beaver pelt or what-have-you. This created inconveniences, because maybe your neighbor doesn’t need chickens right now, so you have to invent money.
…
Think about what they’re saying here – basically: that a bunch of Neolithic farmers in a village somewhere, or Native Americans or whatever, will be engaging in transactions only through the spot trade. So, if your neighbor doesn’t have what you want right now, no big deal. Obviously what would really happen, and this is what anthropologists observe when neighbors do engage in something like exchange with each other, if you want your neighbor’s cow, you’d say, “wow, nice cow” and he’d say “you like it? Take it!” – and now you owe him one.
…
So really, rather than the standard story – first there’s barter, then money, then finally credit comes out of that – if anything its precisely the other way around. Credit and debt comes first, then coinage emerges thousands of years later and then, when you do find “I’ll give you twenty chickens for that cow” type of barter systems, it’s usually when there used to be cash markets, but for some reason – as in Russia, for example, in 1998 – the currency collapses or disappears.