The ability to post and sell textbooks on platforms like Amazon or Chegg depends on various factors, including copyright laws, terms of service of the platform, and the specific permissions granted by the textbook publisher. While individuals may legally sell their used textbooks, sharing or reproducing copyrighted material without proper authorization is generally not permitted.
Textbook publishers hold the copyright to their materials, which means they have the exclusive rights to reproduce, distribute, and sell those materials. Most publishers do not grant individuals the right to freely share or distribute their textbooks without explicit permission. This is because publishing companies rely on textbook sales as a significant source of revenue.
That being said, there are platforms and websites where students can legally access free or open-source educational materials. Some organizations and authors release textbooks under open licenses, such as Creative Commons licenses, that allow for sharing and modification. These textbooks are typically available on platforms like OpenStax, Project Gutenberg, or various university websites.
It's important to respect copyright laws and the terms of service of platforms when sharing or distributing educational materials. If you're interested in making your textbooks available to others, it's advisable to consult the specific publisher's policies or explore open-source alternatives.