食物貨幣（food money）

克里斯‧安德森（Chris Anderson）在Free: The Future of a Radical Price一書，引用歷史學家歷史學家保羅‧詹森（Paul Johnson）的話說：

Most early religious systems in the ancient Near East, and the secular codes arising from them, did not forbid usury. These so-cieties regarded inanimate matter as alive, like plants, animals and people, and capable of reproducing itself. Hence if you lent “food money,” or monetary tokens of any kind, it was legitimate to charge interest. Food money in the shape of olives, dates, seeds or animals was lent out as early as c. 5000 b.c., if not earlier.

也就是說，食物貨幣包括：油橄欖、海棗、種子或者動物。