- Dr. S. Vijay Kumar Every branch of knowledge has its fundamental discovery, in mechanics it is wheel, in science it is fire, in politics it is vote. Similarly, in economics it is the money which is the essential invention on which all rest is based. Money as a means of payment consists of coins, paper money and withdrawable bank deposits. In India, t he rupee and the half rupee coin are unlimited legal tender, while all other coins are limited legal tender up to Rs.10. Today, credit cards and electronic cash form an important component of the payment system. For a common person though, money simply means currency and coins. This is so because in India , the payment system, especially for retail transactions still revolves around currency and coins. The common man knows very little about the currency and coins he handles on a daily basis. Hence, this article.