The price of an airport croissant that Rep. Alexandria Ocasio-Cortez, D-N.Y., referenced Monday in making the case for a $15 minimum wage was offered by a store facing a minimum wage that is $13.60 and set to rise to $19.

"Croissants at LaGuardia are going for SEVEN DOLLARS A PIECE," Ocasio-Cortez tweeted. "Yet some people think getting a whole hour of personal, dedicated human labor for $15 is too expensive??"

The New York congresswoman did not opine on why the prices were so high. One factor is that the current minimum wage for the airport's workers is $13.60 an hour.

In a follow-up tweet, she said: "GOP taking every tweet so earnestly, making my point for me. It’s not an argument against the price of a croissant - it’s about the value of human worth. But I guess that idea is foreign to them since their policies treat people as disposable anyway."

Ocasio-Cortez didn't say where she brought the snack, but the workers there were almost certainly paid at least $13.60. The board for the Port Authority of New York and New Jersey, which runs LaGuardia Airport, last year adopted a $19 an hour minimum wage for all workers, to be phased in at stages. The wage is currently $13.60 an hour, will rise to $15.60 in September, and be fully-phased in by 2023.

The rate applies not just to people paid directly by the authority. All workers at concession stands and other food services are covered employees, even the ones employed by vendors that just contract there.

Ryan Bourne, an economist with the free-market Cato Institute, said that basic economics indicates that costs are passed on to consumers, a phenomenon that tends to be more pronounced in areas where markets are less competitive. "An airport is a clear example of this. A higher minimum wage would therefore lead to higher prices, all else given, because customers have very few options to shop around," he told the Washington Examiner.

Others on Twitter suggested to Ocasio-Cortez that this might be the case. "I am literally on my hands and knees begging you to read this book," tweeted @SteveCampy along with a picture of "Basic Economics" by Thomas Sowell.

Others suggested that the price might have something to do with the fact that she was in an airport with limited options. "How come, when I worked as a bartender at a concert arena, a single domestic beer was $11, but you could get an entire 12 pack for $10? I don't get it! " tweeted Ashley Rae Goldenberg.

Ocasio-Cortez' office did not respond to a request for comment.

[Opinion: Ocasio-Cortez's latest self-own: Expensive airport croissants]