Does Apple offer discounts for teachers who want to buy a Macbook?

Yes. Open the Online Store in your browser. Go to the bottom of the page. In the 2nd column from the right you should see this:

Select the store in which to shop that is appropriate to your grade or college. All items in that store will show their academic prices. Not all products carry an academic discount but they do apply to computers.

In the third column from the right you will find a listing for Refurbished and Close out products. Refurbished computers are sold at reduced prices but carry the full Standard warranty and are eligible for AppleCare+. Academic discounts do not apply to refurbished products because they are already discounted.

You are entitled to the academic discount when you buy directly from an Apple Store as well as an online order. You will need a picture ID that indicates you are teaching faculty.