J.T.
I agree with the previous poster about giving the teachers she's had the longest the original gift cards and just giving the new one a Christmas card. I am in the exact same predicament, and knowing myself the way I do, I will not practice what I preach and will give all three teachers something. But then again, I care too much about other people's feelings at times!
BTW, what a gift it would be if our high school students would do their work!! I'd take that over anything!!
Good luck and enjoy your Christmas break!!