The Red de Trueque in Argentina is one of the many cases of resurgence of non-state monetary systems. Such systems are known with different names in different countries: community or complementary currency systems (CCS), moneda sociale in Italy, local exchange and trading systems in the UK, Canada and the USA, and monnaies parallèles in France. This section reviews the literature on community, complementary or local currency systems.

According to the broadly accepted definition of Ekins and Max-Neef CCS are a self-regulating economic network in which members issue and manage their own money in relation to the needs of a bounded community. Lee refines the concept to a local system of production, multilateral exchange and consumption articulated through single-purpose money independent of, but often related to, the prevailing national currency. The CCS is a complementary economy, fully not-for-profit and operates at the community or inter-household level. In practical terms, it functions as a local association whose members offer and request goods and services priced in a local unit of exchange and then trade those commodities with other participants.

A CCS is created bottom-up by communities and it combines income and identity generation. Other authors (for example, Blanc) emphasize that they are an essentially local phenomenon and affect the local economy, in contrast to official money circulating in a whole country and abroad. The purpose is normally not to disconnect from the national monetary system, but to complement it, adjust it or adapt it. Although they have different names, such systems all share the characteristic of using an interest-free means of payment created by a non-state civil society actor.

As they spread across the world, community currencies adapt to local differences and legal frameworks in a variety of ways. Some communities issue notes or cheques to cancel payments which are accepted by another member. Others fix a unit of value, expressed in hours of work, notwithstanding the type of work offered. The British LETS functions mainly on the basis of an accountancy system: people who provide a good or service receive a ‘credit’ in their accounts which they later use to buy from other community members; everything is managed by a central administrator and a computer.