What we did for dd's teacher who is 23 is since she likes lotions, we got her 2 hand creams (can you imagine the damage done washing your hands nearly 8 hrs a day) and a keepsake stuffed sheep ornament. Classroom supplies are usually appreciated as well as gift cards to various stores.
My kid's school has a rule against sending gifts, but I send it to their homes instead and this year both teacher and assistants will be receiving; gift cards, candles and a beautiful bouquet from Edible Arrangements. All will be delivered the last day of school.
I got her a little set from Yankee Candle with some snowmen on it. My son picked it out of a catalogue from my other son's fundraiser LOL. But you can also go onto Pinterest and search for handmade teacher gifts. I even have one on my blog. Its a jar of M&M's situated in a rainbow and it has a poem on it about the rainbow colors and how much the teacher has impacted your child. I typically do this at the end of the year though:
I told dd to ask her teacher what is her favorite restaurant and plan on buying her a gift card. If my dd doesn't ask, which she will probably forget, I think I may buy the teacher a gift card to the movies or Barnes and Nobel.