The "Student or Non-Profit" option is only for Projects posted by Students or Non-Profit Organizations.
They are clients that have more flexibility in setting their budget for a project as we only allow these clients to set budgets that are less than $100.
Like other client's it's crucial to negotiate the terms before sending any final file.
Their rates can be pretty variable, and it is possible that a project could be quite lucrative or even without pay. It is also possible there can be other incentives involved.
If you are a new voiceover talent or are looking at expanding your demo portfolio, this could also be a great option to keep in mind.