Some libraries are available as subscriptions, for which an annual prepayment is required. They include all updates within an active subscription period (at least three years).
Unlike buyouts, these licenses are not perpetual. This means that you only have a license to use these libraries as long as you have a subscription. After cancellation, you must remove all files from your hard drive. Of course, projects that have already been completed retain their license and can still be commercialized.