Reciprocity constitutes an important exchange system in every society.
Giving may be benevolent, may be used to strengthen existing relationships, to aggressively 'fight' people or 'flatten' them with generosity. But underneath the formal economy lies an informal market system often called the shadow economy. People hunted and gathered or farmed largely for their own needs. But the world market economy has penetrated even the most remote areas and has brought with it a change from subsistence economies to production for money.