Oops! I Craft My Pants (by the way I can't help but smile everytime I read her blog title!) has an idea of giving a bottle of lotion with the saying: "We hope your school year goes smoothly." Interested in a label? She has them all ready for you to use, just head on over!
Eighteen25 used a jumbo calculator (which the dollar store carries) and attached a tag saying: "According to my calculations...this is going to be a good year!" Yup, you guessed it, the tag is there and ready for you to print!
The Rachel Berry Blog made these cute pencil bouquets for the teachers. I think these would be for at any point during the year though.
And finally, this last idea is just completely RIDICULOUS! I saw this idea on Pinterest and thought about how completely AMAZING this supply cake looks, but seriously, I think you would have to L-O-V-E your child's teacher!! It might be a fun gift for the PTA to give to the office staff or have as a centerpiece at a back to school lunch though!