Philadelphia pizza shop customers pay-it-forward, feed the homeless

In late 2013, Mason Wartman, 27, left his job on Wall Street to open up Rosa’s Fresh Pizza, a $1-a-slice pizza shop in Philadelphia.

"I had plateaued at my Wall Street job and had always wanted to own my own business," Wartman told ABC News.

A few months later, a customer asked if he could buy a slice for someone in need.

Wartman had an idea: He drew a smiley face on a Post-It note and affixed it to the wall. The bright square became a voucher for a free slice, to be claimed by anyone hungry or broke.

It wasn’t long until “pay-it-forward pizza” took off.

"The homeless, they come in and say, ‘I hear you give out free pizza to homeless people,’” Wartman told The Salt.

Since that first Post-It, Wartman has seen customers donate more than 8,400 slices, with 30 to 40 homeless people claiming slices every day.

"We keep our food reasonably priced so that our paying customers are able to pre-purchase slices that we give to homeless people in the area," Wartman said.

"This is a super-easy way, a super-efficient way and a super-transparent way to help the homeless,” he added.

While Wartman now keeps track of the pay-it-forward donations on the register, customers still leave notes. One wall is now covered in colourful Post-Its containing short messages of encouragement.

Wartman told WPVI that he treats every customer the same, regardless of whether or not they can afford to pay.

"They deserve to eat in the store and enjoy the music as much as any other paying customer would,” he said of his homeless clientele.

Wartman’s pizza shop recently caught the attention of Ellen DeGeneres. The generous talk show host gifted Rosa’s Fresh Pizza with a $10,000 to help the shop continue its mission to help Philadelphia’s homeless.