For my first grader, the PTO gave the teachers a fancy cup with "SV Staff" on it so I didn't want to giver her a water bottle. Instead I bought a glass container that she'd be able to re-use for left overs or whatever, and I filled it with glue sticks. It says "Mrs. Coulehan, You're the Glue that held our class together... Thanks for sticking with the job! Have a great summer!!!" and I had my son sign it.
She had mailed a thank you note to the house and said that she just loved the gift! She's such a great teacher and I will miss her!!!!
Here's the Jpeg... Sorry his teacher's name is on it. Just paint over it with white and insert your own teacher's name.