Electronic currency is known as e-money, electronic cash, electronic money, digital money, digital cash or digital currency which is exchanged only electronically. Typically, this involves used of computer network, the internet and digital stored value systems. Electronic funds transfer and direct deposit are examples of electronic money. Meanwhile, it is also a collective term for financial cryptogrphy and technologies enabling it.
While electronic money has been an interesting problem for cryptography. Currently, used of digital cash has been relatively low-scale. One rare success has been Hong Kong's Octopus Card system, which started as a transit payment system and has grown into a widely used electronic cash system. Singapore also has an electronic money implementation for its public transportation system (commuter trains, bus, etc), which is very similar to Hong Kong's Octopus card and based on the same type of card (FeliCa).
By the way, if a person goes to a web-site to sell any goods purchases anything things that they desired, these must communicated by e-cash or e-currency. Anyone wish to sell anythings through internet can set any amount. Normally the vendor will base on their own country currency to set the selling price. On the other hand, the person who sell the goods to global will normal set the price in US dollar.
Just buy and sell via internet!! It's very convinience!! The currency can be set as your desired...