I got a few samples at work today with little padlocks from HP and inside when you get the right code there is a slip that tells you to goto
http://www.hp.com/go/2gift
Fill out the form and then at the end use pin code 121 ... i opened several of these and the pin code for each was 121 hope this works i filled it out and got a message saying:
Thank you for your response. We have received your Pin Code. You will soon receive an e-mail from Amazon.com with redemption details regarding your $25 gift card.