Cheapest Immunology 3cr RA undergrad course?

[cookderosa]

A friend of mine is looking to improve her GPA for a potential PA school application. She's looking for a 3cr undergrad Immunology course (RA credit, not ACE) to replace an F she's received in this course previously. I don't think that this will wipe out her F, since it won't be the same course number. I suppose her thought is that she can mitigate the damage done by showing that she can be successful in the course.

So, anyone know of anything that fits the bill? She could retake the course at her university, but that will cost about $1,200 and she's looking for a cheaper option.

Finding an online RA 3 cr immunology course isn't like finding English 101, that's a tough one to even find- let alone cheaper.
FWIW, I'd revisit this with her. Even if it did replace her F (which I think should be done at the same school for that to work, but not the point) does she need it? It isn't a common prereq, it's not part of the premed core and a 3 cr class when added in against 120 credits won't move the gpa needle even a pinch. Are other aspects of her application excellent? I guess I'm saying, this might be a lot of work for little to no return.