Kosher Slurpee List (Chicago Rabbinical Council) 1. When you text SIXFLAGS to 711711 you’ll get a link to a coupon for a free medium slurpee. The coupon is good through 12/31/16. Once you click redeem offer on the coupon page you’ll have 15 minutes to use it. 2. Today through 9/18 when you purchase a Want to continue reading this post? Click here!