I used the TI-Nspire calculators when I was at high school (though not in the US), and found them very capable. Never used an HP Prime, so can't comment there.

I used the TI-Nspire calculators when I was at high school (though not in the US), and found them very capable. Never used an HP Prime, so can't comment there. There's also the Casio FX-CG500 (https://www.casio.com/us/scientific-calculators/product.FX-CG500 https://www.casio.com/us/scientific-calculators/product.FX-C...), though you can't use the stylus in your exams for some stupid reason, so I suppose your finger has to suffice? All three have emulators available with at least a free trial, so I'd recommend installing those and trying them out together.