Non-Microsoft employees are able to purchase logo merchandise on the Microsoft Company Store website:
When you arrive at the homepage, you’ll see both a couple of boxes: a New Customer area to the left and an Existing Customer login box to the right. If you look at the New Customer area, click on the "Non-Microsoft" option, you’ll be able to set up a new account and shop for promotional merchandise. In fact, you’ll see all the same items available to Microsoft employees except for hardware and software!
Would you like to purchase hardware or software at the Microsoft Company Store? Email firstname.lastname@example.org