We provide several options for free PVS-Studio licensing, including the ones for open projects. Specifically for educational purposes, in case if student's works aren't open, the best option is to add the following comment to the code.

For professors' note: use PVS-Studio to get students familiar with code analysis tools

by Andrey Karpov

From the article:

The PVS-Studio analyzer can be regarded as a fine example of a modern static code analysis tool. First, it's a great example to show the abilities of static analysis tools in detecting errors and security defects. Second, you can demonstrate its integration into the software development cycle to enable continuous code control. In its example, you can show integration with such systems as Jenkins, TeamCity, Azure DevOps, SonarQube, Travis CI and others.