L.B.
Hmmm, I think it was a little crass to put that on the calendar...it's one thing to tell the kids in class because they've asked..it's another to volunteer the information. It's almost like she expects to get something. If you feel obliged to do something I would keep it under $10...remember, they'll still get you for X-mas, teacher appreciation day, and end of school year. Frankly, I'd send a plate of cookies/cupcakes so the whole class can celebrate just like they do for everyone else's birthday...no one else get's presents...don't see why the teacher should either.
If you do feel like you need to...here are things that I have given my kids teachers: Bath & Body (lotion, shower gel, body spray, hand sanitizer), cute teacher stationery (thank you cards, post-it notes), teaching supplies (pencils, awards, name cards, bingo games, stickers, stamps, flash cards, etc. to use with the students), a tote bag with their name embroidered on it (great for field trips), a coffee/tea mug with their favorite stuffed in it (coffee, hot chocolate, tea, etc.), jar of candy for their desk for when they need a pick me up & gift certificates to Scholastic to buy books for their classroom.