That specific promo is now over guys! But Society6 is constantly having one promo or another, so if you still want a spectacularishly awesome TPG shirt or swag, please check it out! Get something for your loved ones! Get something for your hated ones just to confuse them!
Also, I would LOVE if you tweeted me @PigeonComics a picture of you in your shirt if you get one, it just makes my day :D