Starting today (because it's "Fry-Yay"), Jack in the Box is running a limited-time deal on their mobile app where you can get a medium order of Seasoned Curly Fries for $1.
A medium order of curly fries at Jack in the Box is normally $3.19 in my area (Los Angeles).
You can find the promotion in the "Menu" section under the "App Exclusives" tab.