I've been back and forth with Amazon, who apparently hasn't a clue on the fine print of the promotion and had to contact DirecTV directly. I'll paste the email I got back from them that entails who is eligible for the promotion.
"Thank you for writing to ask about the Amazon offer that you will get free NFL SUNDAY TICKET.
We are confident that we are providing a wide variety of promotions and offers that our customers can take advantage of. While this is certainly a great offer, it is only for new customers at this time. Rest assured that, as the 2013 season approaches, we will update our offers for existing customers as well. The best way to stay in the loop for any special offers you may be eligible for is sign up for email alerts by logging in at (website removed).
In addition, you may watch NFL SUNDAY TICKET games using your PlayStation®3. However, you must have a base programming package. You can visit our web site at (website removed) to see the wide variety of programming choices we offer. You can also call us at 1-800-531-5000, our general customer support team is available from 8:00 AM to 10:00 PMlocal time daily."
So basically the only way to take advantage of this offer is if you are A, a new DirecTV customer, B, an existing DirecTV customer with NFL Sunday Ticket, or, C, one of those rare souls unable to receive DirecTV service because of where you live. I wish they'd define the promotion a little better, but it is what it is I suppose.
I hope this helps anyone confused, like I was, on the Amazon promotion.
*edit* I've sent one more email to DirecTV to make sure. I'll post the next response I get from them in this thread.