Burger King sells Whoppers for a penny at McDonald's locations to promote its app 

Key Points
  • Whopper fans can buy the burger for only a penny as long as they order within 600 feet of a McDonald's location using the Burger King app.
  • Burger King is encouraging customers to download its revamped app and trolling McDonald's with the promotion.
  • Fast food customers who order using technology tend to increase their spending by 26 percent, according to data compiled by Deloitte.
Burger King Whopper
Chris Ratcliffe | Bloomberg | Getty Images

For a limited time, fans of Burger King's Whopper can buy it for a penny — if they're at a McDonald's restaurant.

Burger King is promoting the relaunch of its app by trolling its rival.

The app uses geofencing to determine if the customer qualifies for the promotion. If you're within 600 feet of a McDonald's location, the burger is yours for a fraction of its usual price. Once the order is placed, the app will lead customers to the closest Burger King. The promotion begins Tuesday and will end Dec. 12.

The enticement of a one-penny Whopper should encourage customers to download the company's app, calling attention to how restaurants are using their apps to interact with their patrons.

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Eighty percent of customers who want to hear from a restaurant say that they want to learn about discounts and special offers, according to data compiled by Deloitte.

But that doesn't mean that they will actually be saving money by ordering online. Ordering via a mobile app or the internet tends to increase a customer's spending by 20 percent, according to Deloitte data. For fast food restaurants like Burger King, that number jumps to 26 percent.

This isn't the first time that Burger King, owned by Restaurant Brands International, has used a stunt to promote its food. This year alone, the burger maker staged a car fire for Good Samaritan Day, created Whopper doughnuts for National Doughnut Day and launched a sandwich to celebrate the Royal Wedding.

It also has a long history of mocking its archrival.

In April, the Miami-based chain released an advertising campaign that showed former McDonald's executives owned grills. (Burger King grills its burgers, while McDonald's cooks its burgers on a flat-top griddle.) Another advertising campaign compared Ronald McDonald to Pennywise, the murderous clown from Stephen King's "It."

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