Labour voucher
Labour vouchers (also known as labour cheques, labour certificates, and personal credit) are a device proposed to govern demand for goods in some models of socialism, much as money does under capitalism.
Outline
Unlike money, vouchers cannot circulate and are not transferable between people. They are also not exchangeable for any means of production hence they are not transmutable into Capital. Once a purchase is made the labour vouchers are either destroyed or must be re-earned through labour. Therefore, with such a system in place, monetary theft would become impossible.
Such a system is proposed by many as a replacement for traditional money while retaining a system of remuneration for work done. It is also a way of ensuring that there is no way to 'make money out of money' as in a capitalist market economy.
Additionally, the only kind of market that could exist in an economy operating through the use of labour vouchers would be an artificial market (arket) for mostly non-productive goods and services; as with the dissolution of money, capital markets could no longer exist and labour markets would also likely cease to exist with the abolition of wage labor which would by necessity occur with the adoption of vouchers.