Looking for online Calc 3 course

I’m going to be a senior this year in high school and last year I did calculus BC. My school doesn’t offer anything higher but I want to take multivariable calc this year. I’m looking for an online course to take during school. I’m already aware of John Hopkin’s course but it’s kind of expensive and I am looking for something that is cheaper. My school is very picky about what kind of course it is and needs to be accredited at some university and have like a grading system with tests/quizzes (basically it can’t be the MIT open courseware stuff or similar). If anyone has any recommendations it would be super helpful.
I’ve been looking at the Uni of North Dakota because they have a 9 month online class for much cheaper than JH. Anyone have any experience with UND online classes?
Thanks