Pre-Industrial Societies: Anatomy of the Pre-Modern World observes that even in relentlessly noncommercialized societies, robust markets existed in two commodities: iron and salt. They were traded on the market within villages that otherwise had little use for markets, and they would make their way by international trade routes to even the most isolated cultures.

For iron, that trade would have mostly been in tools. For salt the only reason is that salt is a vital nutrient and if you can't get enough of it, you die. (Though I think it's worth observing that iron is a vital nutrient too.)