Shake Shack has an offer for Buy One Burger, Get One Free (up to $6 maximum) via their app (iOS or Android) when you use promo code SHAKEITUP.
- Offer is available for one-time use only until 10/26/2018 at all participating Shake Shack locations on the Shack App or in-person at most Shake Shack locations
- Exludes airports, ballparks and stadiums.
- Max savings of $6.
- Minimum Shack App + kiosk order of $10 for offer to apply.
- Discount will be applied at checkout.
- More details here.
Nice offer for Shake Shack fans. You can also stack this with $10 monthly credit from the new Amex Gold card.