FREE medium sub with the purchase of a medium or large sub, chip & drink. call or order online atwww.firehousesubs.com/locations/az/51-baseline/www.firehousesubs.com/locations/az/mill-towne-center/. 2020 Firehouse Subs. This offer valid with coupon at participating restaurants in Arizona. Prices and participation may vary. Limit one per customer, per visit. Not valid with any other offers. Substitutions or additions may result in additional charges. Expires 7-6-20. CODE: SUB$SUBDRINKCHIP. Go to LocalFlavor.com for more coupons.