This is quite common in some markets: although the product is the same, people accept that other customers get a better deal. But it’s more usual in service industries. So museums or shows will offer discounts to certain groups of people. You can even occupy the same seat on an aeroplane for a lower price, just because you’re under a certain age.
But this form of price differentiation has to be accepted, or else you’ll upset many, many customers.
Why do Apple offer such attractive discounts to students? Because they know that one day these students will come back again for more, and more, and hopefully more and more – ie, they’ll become loyal. If Apple can grab enough such customers, they’ll shove Microsoft off its dominant pedestal. So although this eats into Apple’s margin, in the long term it could pay off.
The picture in this post has been doing the rounds in Facebook and forums. What it also shows is that having an Apple also gives you certain street cred. If you don’t use Apple, you become the butt of other students’ jokes.