Free Jiffy Corn Muffin Mix Save 100% when you buy ONE (1) 8.5 oz. box of Jiffy® Corn Muffin Mix. Expires 4/10/2016. Free Jiffy Corn Muffin Mix No related posts. Sign up for our daily newsletter and never miss a deal again! As a subscriber, you'll be the first to know about new offers and discounts on SweetFreeStuff.com! Enter your e-mail: