Licensing
ReaClassical is free and open source software. There is no license key, no activation and no internet check: install it and use it, on as many computers as you like, for your own work including commercial work.
The license
The ReaClassical and ReaEdit scripts are released under the GNU General Public License version 3, or, at your option, any later version. You may use, study, change and share them under those terms. The full text is in the LICENSE file of the project's source repository. The scripts are plain, readable Lua: nothing is encrypted or obfuscated.
Plugins and third-party code
The ReaClassical plugins (RCPlugs) are JSFX files, also released under the GPL. Several build on other people's DSP and keep those authors' licenses and credits, which are stated in each plugin's header and in the Attributions page: for example MIT-licensed code from airwindows, BSD-style code from Thomas Scott Stillwell, and LGPL or GPL code in some of the others.
REAPER
ReaClassical is built on REAPER, which is a separate product made by Cockos Incorporated and is not included. REAPER has a generous evaluation period; after that you buy a REAPER license directly from Cockos. Your use of REAPER is subject to Cockos' license terms.
Your projects are always yours
A ReaClassical project is an ordinary REAPER project: a standard .RPP file with your normal audio files. It opens, plays and renders in any current vanilla REAPER, whether or not you have ReaClassical installed, so there is no lock-in. Your recordings, edits, crossfades, markers and mix all come with it.
Actions that help with problems
Update ReaClassical (Shift+U), ReaClassical Factory Reset (Ctrl+Alt+Shift+F) and Support Info To Clipboard (Shift+F1, also in the ReaClassical menu) are always available. Support Info To Clipboard puts your ReaClassical and REAPER versions (REAPER's includes the operating system) on the clipboard and also reads them out in a message box, ready to paste into a support request.