This story originally appeared on RealTime/STL. St. Louis is one of two test markets for McDonald’s Shakin’ Flavor Fries, free through Sunday. We’re shakin’ things up in #STL w/ our new #ShakinFlavor Fries! Free seasoning w/ any fries purch. now thru Saturday! pic.twitter.com/LRqguyGLu2 — McDonald's STL (@McDSTL) May 9, 2014 Here’s how it works: Buy… Continue reading St. Louis McDonald’s shakes up fries