Because they deserve it.
You know your kids' teachers work hard to help them learn and grow in the classroom, and also you know that's no easy feat. Teachers put so much of their effort into guiding and shaping minds—I mean, think about it, can't you remember a teacher or two that had a significant impact on you as a mentor? So, whether it's the end of the school year or the holidays are approaching, it's important to show the teachers in your life how much you appreciate them. You don't have to go over the top—a small, thoughtful (and useful!) gift will do the trick—but something that tells them you value their work and care can go a long way.
All of these gifts keep that in mind, with plenty of personalized, practical options, not to mention a few kitschy, teacher-themed items they'll appreciate and some beautiful keepsakes. And they're all $25 and under, so you don't have to break the bank (especially if you have more than one teacher to buy for) in the process.