I LOVE Firehouse Subs! I’m super excited that they are offering a Tax Day Freebie this year in the form of a FREE Medium Sub!! The catch? You do need to show the cashier this offer here, and you will need to purchase a full-priced medium or large sub, chips, and a drink. You can save the free sub for lunch the next day, or go with someone and split the cost (and purchase an extra drink).