Depending on your particular needs, you may license Media Center Master for use on one computer per month or year (expiring licenses) or you can purchase a lifetime license (which never expires). Each license is only valid for one installation. If you want to run premium features in Media Center Master from multiple computers, you will need a separate license for each installation that you want to use those premium features at.

If, however, you have already purchased a license, but have changed your computer's installation in some way that your license no longer works, or you would like to transfer your license to another computer or installation, you can do that at any time for free by using the Revoke License tool here at the website.

Note: as of November 20th, 2013, Google Checkout/Wallet support has been discontinued by Google. They have an API allowing in-app purchases of digital goods, but it is not supported at this time.