For Matt Kepnes, who has spent most of the last decade as a permanent traveler jockeying through Southeast Asian bus terminals and Eastern European hostelry, New York’s Barney Greengrass deli on a Sunday morning must feel familiar in some ways: tight spaces, gruff uncomprehending waiters, old women elbowing past you in line.

But then you look at the well-heeled crowd, and then prices on the menu. Kepnes’ book is called How to Travel the World on $50 A Day, and it is, in part, a practical guide to staying out of situations like this: a menu without mercy, where a bagel with lox will set you back $20 with tip and tax. Embracing the irony, we settle for something that will total just a bit over the daily budget described in his book: a platter of smoked sturgeon and nova, big enough for two, but not nearly enough to be the only meal of the day.

Immediately Matt begins making his calculations: the $50 spent on breakfast isn’t just a matter of currency. It is, instead, a unit of travel lost. Get sucked into a meal that’s too pricey somewhere in the states, he says, and you’re giving up travel elsewhere. “You could get a couple of days in Central America for this,” he says, “or a couple of days in Southeast Asia, probably a day in a half in Eastern Europe, half a day in Scandinavia, no alcohol included.”

It’s instructive math, because this is what his book aims to do: look at budget travel globally, and figure out how all the parts might fit. It’s not a guidebook, not a place to look for the best hostel in Phnom Penh. Instead, it tells you how to save by region. And the $50/day is not a daily accounting, but an average, including airfare, of a typical round-the-world trip.

“The assumption of my book is that you’re going to spend a year, that you’re going to go on a typical round-the-world trip: South America, Central America, Europe, Southeast Asia, Australia, New Zealand, and back,” he says. “You’re going to spend more than $50 a day in Europe, and something closer to $20 in Thailand.” As an example: one of his favorite towns, Bordeaux, is a city without hostels. He doesn’t recommend skipping it just because you can’t find a $10 bunk with banana pancakes for breakfast. Instead, spend the extra bit on a hotel there, knowing that you’ll be able to more easily save that money in, say, Laos.

In fact, for a well-known budget writer, Kepnes goes out of his way to rib the true misers. “There’s someone online with a kindle book: How to Travel on $20 a Day. Someone else wrote a guide to traveling for free, which is basically a freeloader book. You freeload off everybody, be a stowaway on ships, that kind of thing.”

“You could do it just by couchsurfing, cooking your own food, [taking] overland travel the whole world, never drinking a sip of alcohol, only visiting free attractions,” he says. “But how realistic is that, and then what’s the point? Why come all the way to Italy to end up cooking cheap pasta in your hostel?”

“If this is the trip of a lifetime, you can’t say, I’ll do it next time. There probably won’t be a next time,” he says. “Most people who are traveling just go home and get a job, and before you know it, the years have gone by, and they’ve never gone back.”

That’s a rather clear-eyed appraisal of his readership, which actually skews less toward the serious round-the-world backpackers and more toward people who, as he puts it, are going to Europe for two weeks and want to know how to save money doing it. And he’s happy to give that advice, for as broad an audience as possible: “I want to be a Rick Steves for this generation,” he says, as we negotiate who will take the last of the sturgeon (me) and who gets the lox (him).

That aspiration surprises me a bit. Steves only writes about Europe, and whenever I check in on Kepnes’ Twitter feed, there’s a lot more Asia, Australia, even some Africa, in there. And Steves, as righteous as he is on, say, the legalization of marijuana, has a gee-golly travel persona that hardcore travelers could find grating. But Kepnes, still in his early 30s, is not like most hardcore travelers. He wants to make a career out of this, and so for him, it’s Steves’ business model, not his entry-level travel style, that he wants to emulate: “He’s the expert. [I want to] be America’s travel expert.”

And so: the book. And a new life in Manhattan, home of the $50 smoked fish breakfasts. “After seven years on the road,” he says, “I want to come home to a bed and a kitchen instead of continually crashing on people’s couches in New York City.” His rent comes out to $50 a day, the same amount he used to spend on everything—room, board, and travel—each day when he was overseas. But even in New York he sees some budget hacks that seemingly everyone knows except the tourists who come to visit. The museums are free [or at least have only suggested admission prices]. Broadway gives it away at TKTS, or you could just line up to watch a free taping of a TV show. Subway monthly passes are a good deal, and walking instead of taking cabs is possible in a lot of cases.

Though he’s only been here a short while (his only previous time in the city was a couple months in the summer once), he’s convinced he has found home. “If I’m gonna stop somewhere in America, it’s going to be here. [New York] reminds me of Asia.” he says. “I can’t deal with suburbia. It’s too quiet.” He knows this from experience, having grown up in Winthrop, Mass., a little idyll of a Boston suburb that bills itself as the “gateway to the North Shore”. He jokes that his parents might be tempted to write a rebuttal to his book, called “How to Keep Your Kid at Home”. But for him, life in the shadow of Logan Airport was too placid.

Interview over, we stand up. I go to give my credit card to Gary Greengrass, the middle-aged grandson of the deli’s founder. Greengrass, nearly buried behind piles of old ledgers and notebooks, tells me something that deep in my lizard brain I already knew about the deli: it is still cash-only. And I don’t have a dime on me, nor has my replacement ATM card made it to me yet. So it’s Kepnes who heads out into the below-freezing city to bring cash back from a nearby bank. I pay him back through PayPal the next day, but the realization is hard upon me: even in my own town, I am a tourist, and a wasteful, ignorant one at that.