If you're looking for the most "bang for your buck" - congratulations, your search is over! idTech3 is available through the same GPL (free) and non-GPL ($10,000) options.
Many people don't realize exactly what releasing the source under the GPL means, or understand how to exploit the opportunity to use it. Thus, idTech3 is perhaps one of the most under-utilized game technologies available. If you have a team that is long on talent but short on cash and need a proven engine to develop a game that CAN be distributed commercially, it doesn't get much better than "Free". If you abide by the GPL terms, then this technology is truly a gift from id. Unlike some "bargain" licensors, we don't impose ANY restrictions on your distribution channel (retail, internet, etc.). This is the perfect way to get noticed as a company or design team, as you can do something cool - and get paid, too.
You do not need to get permission from id to start working on your project using idTech3. Just go to this link to download the GPL code and be sure to abide by the GPL terms. Please see http://www.fsf.org/copyleft/gpl.html for further information about the GPL and a copy of that license.
If GPL does not work for you, we offer a "non-GPL" engine license for a flat fee (no backend royalty) of $10,000 per title (for the original engine owned 100% by id Software - not including any of the open-source GPL modifications that have been released for the engine). So you can grab the source and tools from our FTP site and sign a separate agreement with us, allowing you to keep your source modifications confidential (if you like).
If you are interested in id Tech 3 and would like to experiment with it before contacting us, simply purchase a copy of the game, then download the "Quake III Arena" packages from our Technology Downloads page.
