The revenue streams are the main source of income for an organization. The revenue stream can be generated by various sources such as direct sales, subscriptions and advertising. The most common type of revenue stream is direct sales. In this case, the client buys products or services from the company they are buying from. This type of revenue stream is more common in small businesses than large ones. Another type of revenue stream is subscription based, where clients pay a fee to use their services for a specific period of time. This type of revenue streams are more popular in large organizations such as universities and hospitals that have long term contracts with clients and need to generate continuous income from them.