Courseau is a fantastic tool for building a online courses. This tool can mix information from different places like YouTube videos, audio files, websites, and PDFs, and make a course using all these sources. This will save you so much time from researching and summarizing the information. However, the free version is limited to using just one source. For accessing multiple sources, Courseau provides a subscription service with plans at $39 and $99 per month. The premium plan, priced at $99, leverages GPT-4 technology to facilitate the creation of detailed, long-form courses.