Is it ethical to do paid literature searches of research journals for other students? Is it unethical to research journals for other students?

For example, a student is researching gifted students and their subsequent ACT/SAT scores.  Then:


Would it be unethical for me to research educational journals and give the student the title of articles that pertain to their research?
Would it be unethical for me to charge for this?
What would be unethical is for the other person to misrepresent work that you did as having been done by them, or for you to knowingly aid someone in such a misrepresentation. It’s important to credit people for the work that they’ve done.

There's nothing intrinsically unethical about the work you describe, or about charging people for it.