Yes, PDFCreator is really free and may be used without paying money to the authors or anyone else and your rights on the documents you create with PDFCreator are not changed in any way. That does not mean, that PDFCreator has no license. Just these licenses grant you the right to use PDFCreator and to give it to anyone you like without charge.

The PDFCreator Setup is a package of multiple software components. The PDFCreator team took care to only require components, that are free. Each component has it's own license.

Each license allows to download, install and use PDFCreator in a private or commercial environment. They also allow to distribute PDFCreator to as many people as you like, if it is free of charge. The licenses do not interfer with your rights on the documents you process with PDFCreator - they will always be yours.

Selling PDFCreator must be allowed by the respective parties. Maybe additional licenses have to be bought to sell the software bundle. Also is not fully clear, which impact the usage of ActiveX-Interfaces has on the license of the using software. If you plan to use PDFCreator in a commercial software, you should check this with a lawyer.