money is a means of circulation, that is, money acts as a medium of commodity exchange. We usually see the function of money in the process of buying and selling goods, which belongs to this kind. Therefore, this function is also called purchasing means. It goes without saying that currency as a means of circulation cannot be a conceptual currency, but must be a real currency. Any capitalist will never allow someone to take away his goods with empty words. "Means of circulation" is from functions of money's point of view, emphasizing the role of money in commodity exchange as a medium of commodity exchange.
under the condition that money performs the function of circulation means, commodities are no longer exchanged directly with each other, but are exchanged by money as a medium. Commodity owners first exchange their own commodities for money, and then exchange money for other commodities. This kind of commodity exchange with money as the medium is called commodity circulation. The transition from barter to commodity circulation means that the internal contradictions of commodity economy have further developed. Because, under this condition, selling and buying are divided into two independent processes. If people who sell goods don't buy them immediately, others' goods will not be sold. In other words, the function of money as a means of circulation already includes the formal possibility of economic crisis. The means of payment came into being with the sale on credit "
After the appearance of money, people paid for things in cash. With the development of commodity economy, there has been a sale on credit. When the credit purchase expires and the debt is paid in currency, the currency will perform the function of payment means. As a means of payment, money can also be used to pay rent, interest, wages and taxes.
Money, as a means of payment, can make goods circulate in the absence of cash, which is beneficial to the development of commodity economy. Moreover, because some debts can offset each other, money is no longer needed as a means of circulation, which can save the amount of money needed in circulation.
At the same time, money, as a means of payment, also expands the contradiction of commodity economy. Under the condition of payment means, many commodity producers have a task relationship by buying and selling on credit, for example, A owes money to B, B owes money to C, and C owes money to D. If any one of them fails to repay the debt on time for some reason, it will affect other series of people to pay the debts, and the resulting chain melons will make many commodity producers unable to continue production due to lack of money. This is how the "triangular debt" between enterprises in China's current economic life comes into being. Only by reforming, developing production and paying off debts on time can we get rid of the chain lock of "triangular debts".