Freigeld

As part of the theory of Freiwirtschaft, Freigeld ('free money', German pronunciation: [ˈfʁaɪɡɛlt]) is a monetary (or exchange) unit proposed by Silvio Gesell.

According to Gesell, all human-produced goods are subject to expensive storage, whereas money is not: grain loses its weight, metal products rust, housing deteriorates.

John Maynard Keynes renamed the concept of basic interest articulated in Gesell's book The Natural Economic Order with the more familiar term liquidity preference.

The demurrage associated with e-gold is arguably expended by the currency operator to help cover real storage costs.

Bernard Lietaer's terra is a commodity basket currency proposal similar to Keynes's bancor or L'Europa (The idea to establish a L'Europa – monnaie de la paix from early concepts presented in an article in the French newspaper Le Fédériste on 1 January 1933) and bearing a demurrage charge.