there is good reason to believe that barter is not a particularly ancient phenomenon at all, but has only really become widespread in modern times.
Certainly in most of the cases we know about, it takes place between people who are familiar with the use of money but, for one reason or another, don’t have a lot of it around.
Elaborate barter systems often crop up in the wake of the collapse of national economies: most recently in Russia in the ’90s and in Argentina around 2002, when rubles in the first case, and dollars in the second, effectively disappeared.
The more frequent solution is to adopt some sort of credit system.
When much of Europe “reverted to barter” after the collapse of the Roman Empire, and then again after the Carolingian Empire likewise fell apart, this seems to be what happened. People continued keeping accounts in the old imperial currency, even if they were no longer using coins.
Similarly, the Pukhtun men who like to swap bicycles for donkeys are hardly unfamiliar with the use of money.