how much to give teacher for christmas

Well, it depends on a few factors. How much do you want to spend? How close are you to the teacher? And what is the teacher's personality like? If they're a fun and lighthearted person, a small gift like a coffee mug or a nice pen could be a good choice. If they're a more serious and professional person, a more formal gift like a gift card to a nice restaurant or a bottle of wine could be more appropriate.