Metered services (also called pay-per-use) is any type of payment structure in which a customer has access to potentially unlimited resources but only pays for what they actually use. Metered services are becoming increasingly common in enterprise information technology (IT) environments. With utility computing, for example, a company can purchase computing resources to match fluctuating needs. This approach is promoted as being more cost-effective for the company than maintaining a large infrastructure that exceeds the company's average computing power requirements.
Metered services are also gaining popularity in the consumer market. Some Internet service providers (ISPs) have begun to charge customers according to usage instead of charging a flat monthly subscription fee. A growing number of entertainment Web sites also use a pay-per-use structure. Apple Computer's iTunes, for instance, allows users to sample over 2,000 music sample files for free, but charges the user a small fee for a complete download of any given song.