Any business with over 100 nodes has no issue for paying for software and complying with licensing requirements for quality products that serve their business. Much trickier analysis for individual consumers, home based businesses, start-ups etc.. Brand recognition and good will is an intangible that plays into the pricing scheme. Dotnetnuke Corporation recognizes these differences and provides advantageous licensing terms for everyone. If you desire more than the "its free - don't sue us - enjoy. but use at your own risk" you can contract and pay $$$ for a privileged relationship. This seems very fair and proper.
Two Options: Open Source - Free Software (No liability or promise of support, or application use) or Commercial for Customers who are using the software for business and willing to pay substantial money for support, documentation and a business relationship.
The Joomla camp, for example, are having issues with new licensing terms and restrictions imposed on developers for their version 1.5 platform (Forcing specific license terms). As such many reputable commercial publishers are not releasing products or support for this new platform. Many of the larger businesses, under the advice of their legal departments or company policies can not use software with this type of licensing.
The shrink wrap software industry has been faced with these same pricing issues for years and are a good model to study. A pretty simple and effective model with great marketing exposure building good will and community support is the Free for non commercial use (good place to work the kinks out - donations of $ and time - ad supported etc) and commercial license for business use. Our experience has been free use to $100 for individuals for non commercial use and $100 - $1,000 for commercial licensing schemes.