Since the 1830s, barter in some western market economies has been aided by exchanges which use alternative currencies based on the labour theory of value, and which are intended to prevent profit-taking by intermediaries. Examples include the Owenite socialists, the Cincinnati Time store, and more recently[when?] Ithaca HOURS (time banking) and the LETS system.
Michael Linton originated the term "local exchange trading system" (LETS) in 1983 and for a time ran the Comox Valley LETSystems in Courtenay, British Columbia. LETS networks use interest-free local credit so direct swaps do not need to be made. For instance, a member may earn credit by doing childcare for one person and spend it later on carpentry with another person in the same network. In LETS, unlike other local currencies, no scrip is issued, but rather transactions are recorded in a central location open to all members. As credit is issued by the network members, for the benefit of the members themselves, LETS are considered mutual credit systems.