A quote from the link above to give you a flavour of the concept:

Gesell's theory of a Free Economy based on land and monetary reform may be understood a reaction both to the laissez-faire principle of classical liberalism as well as to Marxist visions of a centrally planned economy. It should not be thought of as a third way between capitalism or communism in the sense of subsequent "convergence theories" or so-called "mixed economy" models, i.e. capitalist market economies with global state supervision, but rather as an alternative beyond hitherto realized economic systems. In political terms it may be characterised as "a market economy without capitalism".