For those of you that got the launch package which includes 250MB of free data usage, activating the promo may be a challenge. Sony’s blog has a good FAQ on setting up your DataConnect plan. But for those of you who are more visual, I’ve taken some screenshots of the steps I took to find it. This assumes you already have an active data plan, which is a requirement for the promo to work anyways.
Sign in, and you will see an Accounts Overview screen. Make sure “My Devices and Plans” is expanded, and also expand your actual device. Scroll down a bit, and you will see the “Add a Plan” button. Click that.
Scroll to the “Payment Type” section, and select the last option: You have earned coupons. Your promo code should now show. Once you click on that, it tells you that the promo will take effect immediately unless you set a date for it to become active. I plan to activate mine after my current month runs out instead of doing it now. Hope that helps!
Source : Sony Blog