I'm not sure how old your kid(s) are, but a handwritten card telling the teacher what she or he did that was special, fun, or memorable up to this point is always appreciated. Teachers constantly get complaints and criticism (a lot of it comes from this very site!!!) and we love positive reinforcement; it keeps us going during the rough days. Even a little thank you is always nice. Other than that, if you're baking for the holidays, give a few cookies to the teacher. Have your child decorate an ornament, even covering up an old one you have and making it "new" is free and original. It truly is the thought that counts for us teachers... we don't expect or want expensive gifts, just a little appreciation for all we do.
Wow, Cheryl B., I've been teaching for 15 years and have seldom come across such resolute harshness! Of course it's fine when families can't give gifts to teachers, or choose not to, but to not even entertain the idea in the first place??