Sign up for HBO NOW, like, right now
This is, hands down, THE way to get your GOT on without paying. While you won't be able to watch along with the live broadcast, HBO has announced it will release the season premiere to HBO GO and HBO NOW members at 9pm on Sunday -- in other words, you'll only be 30 seconds behind the live broadcast, tops. AND, since your membership comes with one free month of the service, you'll be able to repeat this for the next four episodes (if you sign up after 4/22). That's half the season, totally free.