Wendy's is offering a FREE Large Fry with ANY Purchase when you use the offer in their mobile app. Buy a small soda or 50¢ Frosty and get the fries for FREE! Offer is only valid for a limited time. If you don't already have the app, click this link then to download it for free and create an account. Open the app, tap on your "Offers" then do not tap the "Use at Restaurant" button until you are at the store and ready to redeem.