Home » Food » Buy One Big Mac®, Get One for $0.50 Buy One Big Mac®, Get One for $0.50 Editor April 6, 2019 FoodMcdonalds SaveSavedRemoved 0 Deal Score0 45 Buy It Now Deal Score0 Buy It Now For a limited time, only in our App Offer Valid thru 4/28/19 at participating McDonald’s. Valid 1x/Week. See McD App For Details. Mobile Order & Pay At Participating McDonald’s. McD App download and registration required. ©2019 McDonald’s.