I spent my entire high school career without a graphing calculator. I used a Casio that cost about $15. And I did Advanced Maths and scored over 90% in the HSC (Australian equivalent of the SAT). Why do you need a graphing calculator to begin with? Why is the curriculum structured to need one? Don’t students know how to graph with a pen and paper? That’s what we in Australia do. None of the students at my school ever used a graphing calculator. And I don’t think we were disadvantaged in any way.