Microsoft has applied for a patent on metered, pay-as-you-go computing. U.S. patent application number 20080319910, said that in the future a PC will be given away or heavily subsidised by someone in the supply chain.

The user then pays to use the computer, with charges based on both the length of usage time and the performance levels utilized, along with a "one-time charge."

While the user could end up paying more for the hardware they would benefit by having a PC with an extended "useful life." The computer would have  scalable performance level components and selectable software and service options and has a user interface that allows individual performance levels to be selected.

This scalable performance level components may include a processor, memory, graphics controller, etc. Software and services may include word processing, email, browsing, database access, etc. To support a pay-per-use business model, each selectable item may have a cost associated with it, allowing a user to pay for the services actually selected and that presumably correspond to the task or tasks being performed," the Patent said.

If such an idea ever happened, the user would be locked to a certain supplier and the whole thing would be controlled by metering agents and specific elements of a security module. It also means that PC performance could also be defined by the user.  If all they are doing is browsing, then they could use a lower processor power, but if they do online gaming  the highest available performance may be made available to the user.

The user only pays for the performance level of the moment, the user may see no reason to not acquire a device with a high degree of functionality, in terms of both hardware and software, and experiment with a usage level that suits different performance requirements, the patent said.