No, Unity does not charge on a per title basis and you do not pay royalties or pay revenue share, even for games and applications made with the free version.
Yes you can create and sell a game with the free version of Unity, without paying royalties or any revenue share. However, Unity Free, which includes the free platform add-on products, may not be licensed or used by a commercial entity with annual gross revenues (based on prior fiscal year) in excess of US$100,000, or by an educational, academic, non-profit or government entity with a total annual budget for the entire entity (based on prior fiscal year) in excess of US$100,000.
No, You may not combine or integrate content you develop with Unity Free simultaneously with any content you develop with Unity Pro or any Unity Pro Add-on Products. (See Section 2a of the EULA).
Yes, all assets in our tutorial and example projects may be used in both commercial and non-commercial use in Unity-based projects. The assets themselves may not be resold, however.
Android and iOS build options do come with the free version of Unity, however, if you wish to build to these platforms with the Pro features then you will need the Android and iOS Pro add-ons.
Subscriptions to student licenses are available through Studica. We also have educational licenses available to accredited educational institutions. Schools can contact us using our contact form for more information. Note that reduced-price versions available through Studica have a single activation and not the two activations that you get when you purchase a full-price Unity from the unity3d.com web store.
We license Unity source code on a per-case and per-title basis via special arrangements made by our business development team. As this can be quite expensive, we do not generally license source code to smaller operations, educational institutions, nor to companies in countries which do not have adequate legal intellectual property protection.
We offer a special extension of the Unity Webplayer which can cache asset bundles locally. This is licensed under an agreement made by our business development team. Generally it is licensed to developers with a large anticipated revenue and not on a smaller scale basis.
No, Subscription add-ons cannot be added to Perpetual licenses. However, perpetual license holders are eligible for a special price on a Unity Pro subscription. For example, for only $80/month a perpetual license holder can subscribe to Unity Pro and one Unity Pro add-on. Please see the sub-category, “Subscription offer for perpetual license holders” under the Subscription FAQ
Unity 4.x and 5.x Owner:
You can now return activations via your web store account, this was created to allow Unity Pro 4.x owners to revoke their own machine activations. Go here to start.
Unity 4 users can also return their licences within the editor:
Open Unity 4
Click "Help"
Click "Manage Licence..."
Click "Return Licence"
This must be done prior to reformatting or a hardware change. You must also have an uninterrupted connection to the license server. This does not tend to be the case when behind a proxy or being without internet connection.
Unity 3.x Owner:
You will need to e-mail the support team via support@unity3d.com with the following information:
The Serial number you are using (R3/U3-XXXX-XXXX-XXXX-XXXX-XXXX)
The name of the individual the Serial has been assigned to (Ben Stoneman)
The name of the machine you wish to migrate from (Ben-PC/ Ben's iMac)
Unity 4 users can now return their licences within the editor:
Open Unity 4
Click "Help"
Click "Manage Licence..."
Click "Return Licence"
This must be done prior to reformatting or a hardware change. You must also have an uninterrupted connection to the license server. This does not tend to be the case when behind a proxy or being without internet connection.
This error is caused when the information contained in the license file no longer matches the machine it is living in. This can commonly be caused by reformating a machine and using the old license file.
Give the steps below a try, and let me know how you get on! The files may be hidden.