There’s no such thing as a free lunch anymore at Panera.

The sandwich chain will close its last pay-what-you-can location this week after determining the model wasn’t sustainable. It’s already shut the other free-meals cafes around the country, including locations in Chicago; Clayton, Mo.; Portland, Oregon; and Dearborn, Mich., and its Boston concept will close its doors Feb. 15 after a six-year run.

The original idea was to allow customers to give a suggested donation for their food in a bid to raise awareness about hunger across the U.S. The funds collected were supposed to cover the store’s operating costs while also paying for those who couldn’t afford their food.

“Despite our commitment to this mission, it’s become clear that continued operation of the Boston Panera Cares is no longer viable,” Panera Bread said in an emailed statement. “We’re working with the current bakery-cafe associates affected by the closure to identify alternate employment opportunities within Panera and Au Bon Pain.”

The JAB Holding Co.-owned chain said that those who couldn’t afford their food, including homeless patrons, were supposed to eat in-store. That was intended to create a feeling of community, but it also highlighted the tensions that arise when private businesses try to be welcoming for everyone — a challenge rival Starbucks Corp. has also faced.

Starbucks has been training workers to treat anyone who walks in the door as a customer — whether they are making a purchase or not. The coffee chain is still trying to mend its image after a highly publicized controversy last year when a store manager called the police on two black customers who later said they were waiting to start a business meeting.