Smashburger is joining in on the 420 celebration this year by offering 4 burgers for only $20 on April 20, 2024! The special deal is valid on the in-store purchase of four single Classic Smashburgers. The Classic Smashburger comes with certified Angus beef, American cheese, lettuce, tomatoes, red onions, pickles, Smash Sauce, ketchup, all placed between a toasted bun.