The current gen Macbook Air comes with a speedy Core i5 CPU with powerful Intel HD 4000 graphics. They have a high def webcam, high def screen and give you so much more for your money versus the glasses or bag.
Buy whichever you need. I personally don't think that I would spend so much money for sunglasses or a bag, but a Macbook is great stuff it is worth the money. Of course it depends on whether you are in need of any of them, and if yes, which one.