How Do You Get $25 Google Play?

One question I was wondering when I bought the Nexus was how do I know whether I am going to get the $25 credit from Google Play? This credit is supposed to come with the Nexus7 along with the free movie Transformers.

Do not log in using a friend's gmail account when you first turn on your Nexus7 unless you want to give them your $25 credit

When you turn on your Nexus7 and you log into your Gmail account, you will receive an email from Google welcoming you to the Nexus 7. There will also be another email sent to the same address with the following welcome message.