Burger King: FREE Fries March 17 -18 This post may contain affiliate links. Please see the full disclosure policy here. Posted on March 16, 2012 Written by Mary Leave a Comment Stop by Burger King this weekend (March 17-18) for FREE Fries & Green Heinz Ketchup! You have probably seen this all over the TV – but in case you missed it! Don’t miss your FREE FRIES!