With student loan debt hitting crushing levels – the average student today is graduating $28,000 in the red, many with tens of thousands of dollars more debt – a new smartphone app helping college students save money has attracted a lot of interest.

It’s called TUN, for “The University Network,” and in Boston and dozens of other college towns across New England and the nation, it collects and shows on a map all the businesses offering student discounts nearby.

“It’s just really easy to see that, like, this is down the street,’’ said TUN user Annabel Sanchez, a Boston University junior and mathematics major from New Jersey, who’s discovered great discounts from places she enjoys eating out when she can, like Sunset Cantina and Tasty Burger. Around the BU campus, she’s learned through TUN, “There's a lot of small businesses around’’ offering meal deals or discounts … It really is good for when I do want to go out. A couple of dollars here, a couple of dollars there, everywhere I go out to eat.’’

Besides cataloging discounts, TUN lets students collect points towards freebies by doing things like reporting to TUN businesses with student discounts that they had not known about; sending pictures or reviews of places they’ve gone and used TUN discounts; or doing a FourSquare-style “check-in” when they go to a restaurant or store on the TUN network.

“Everyone wins,’’ TUN founder and CEO Peter Corrigan said. “The merchants are getting customers that become loyal customers. The students are getting things at a discount. And students are getting free things when they help promote local merchants.’’

For companies hoping to get listed on TUN, Corrigan said, “It's free for small business. It's completely free. There are bigger companies that we work with that gladly pay money to work with us, but for the smaller merchants, it's completely free.’’

We met for interviews at one of the Boston businesses in TUN, the Fitness Together location on Hanover Street near Haymarket in Boston, which offers a 15 percent discount to college students. Less than two weeks after signing up, owner J. P. Krueger said, they landed their first young customer. Krueger said he sees great value in the app for his business. “College students, they love to work out, they create a great vibe in the studio. We have group classes that work really well for students that can't afford the personal training.’’