License
The source code of the project is licensed under the Apache 2.0 license. For the license of the used libraries you have to check the respective sources.
Stable, supported binary builds of ownCloud Infinite Scale that will be distributed by ownCloud GmbH are covered by a non OSS Freemium License EULA. This protects additional efforts that ownCloud GmbH is putting into these builds.
Since the source code of Infinite Scale is available under free licenses, the free usage can, should and will not be limited in general.