There's a limit of five discounted shakes, floats, or ice cream slushes per customer at participating restaurants.
If the deal sounds familiar, Sonic has been offering shakes, floats, and ice cream slushes for half-price after 8 PM all summer long. That promotion is slated to end on Labor Day, September 3, 2018. Snow Cone Slushes and the $2.99 American Classic deal are also set to end on the same day.
Photo via Sonic.