Free burger at Shake Shack

http://baltimorecheckbook.tumblr.com/post/156973859247/free-burger-at-shake-shack#_=_

Get a free eats at Shake Shack using the restaurant’s new iPhone app.

The offer, valued at up to $5.55, gets you a free ShackBurger, hot dog or breakfast item by downloading the free app, creating an account and using the promo code “SHACKAPPY” at checkout.

The offer is good only at participating…