There's no purchase necessary to redeem your free Slider but the coupon is only good on May 15, 2020 at participating White Castle restaurants at the drive-thru. You can find the coupon on their website here.
You can choose any slider you like, while supplies last, except for Double Sliders and the 1921 Slider, which are specifically excluded from the promotion.
In other deals, White Castle is offering a 20 percent discount on all orders placed in-person by frontline workers from May 15 through June 15, 2020. Frontline workers include EMTs, healthcare workers, as wells as grocery store and food retail employees.
Photo via White Castle.