I've been now teaching several remote math lessons with a standard iPad $329 and Apple Pencil $99. Basically I'm joining to a Teams meeting and sharing the entire screen, then writing stuff using the standard Notes application. Finally I share the note with the class by exporting it to the Teams application.

There is a built-in feature in Teams which allows me to launch quick improvised quizzes in the chat which I find nice. I'm also able to collect assignments via Teams and check/mark them in Word using Apple Pencil. The students take a picture using their own phone camera and add it to a docx-file which is then turned in using Teams.

The basic iPad is $329. It is a modern fast computer that has everything built-in. The only things you need to add is a keyboard and/or a stand/case.

Apple hardware is no longer expensive these days — I mean, they will let you spend as much as you want and take your money, but their lineup starts quite low and provides excellent value for the money.