FREE Medium Slurpee at 7-Eleven09/30/2015 3:00 pm To get a FREE Medium Slurpee at 7-Eleven text message SIXFLAGS to 711711 on your cell phone. Click the “Redeem Offer” button When you are ready to redeem the offer, since it is only valid for 15 minutes once you clicked it. Expires 12/31 Latest Freebies