Teachers should usually be a piece of cake. Gifts could be maybe their favorite book if they are an english teacher, or could be as easy as giving them cookies or cake. My mom, when I was in grade school, painted ceramics for my teachers and I would give them that at the end of the year.
Go for something mostly business, with a flare of personal, and something that will last. A customized coffee mug, a potted plant, or a pretty picture frame are all great for teachers.