From wikipedia:
Contrary to popular conception, there is no evidence that societies relied only on barter before using money for trade.[73] Instead, non-monetary societies operated primarily along the principles of gift economics, and in more complex economies, on debt.[74][75][76] When barter occurred, it was usually between strangers or would-be enemies.[77]
There were multiple books that helped you understand that term?
There’s been a few of them. A People’s History of the United States, 1491, and Humankind are some good examples