Dallas, Texas, 2016-Jul-08 — /EPR Retail News/ — America’s favorite frozen drink turns 50 this year, and 7‑Eleven, Inc. is celebrating its birthday – 7‑Eleven® Day, aka July 11, aka FREE SLURPEE DAY -- in a BIG way. To celebrate Slurpee Fiftee and 7‑Eleven’s 89th birthday, participating stores will give away an estimated 9 million free small Slurpee®…