ManyCam is available in Free and Pro versions. The free version is quite robust, but a Pro license unlocks additional capabilities such as creating more presets, using more audio sources, removing the ManyCam watermark, and accessing all picture-in-picture modes. The version you're considering is typically a fully pre-activated Pro or Enterprise edition.
: Teachers can overlay drawing boards, display digital textbooks via screen sharing, and keep young students engaged using digital props and effects. ManyCam v7.8.0.43 Multilingual Portable -FTUApps-