This man is off on a round the world trip - and all for free

A 28-year-old writer is about to embark on a two-month world trip involving 21 flights - and all for free.

Scott Keyes, a writer for Think Progress, has become an expert on gaming credit card airmiles offers and frequent flyer schemes. And he's now set up a 20,000-mile trip taking in 13 countries, with all his flights and hotels already covered.

To stack up the points, Keyes has 25 credit cards. He then researches thoroughly the best ways to use them, picking the flights and hotels that need the least number of points.

This next trip, he says, took 10 to 15 hours to plan.

"It's not necessarily easy or intuitive for beginners," he told Business Insider. "But the good news is that because if you do a little bit of leg work - learn how to get a few miles and how to use them well - you can start to travel really, really well."

In the past, Keyes has flown from New York to Milan for $65, visited the Galapagos Islands for $45, and travelled to Belgium for under $150. He's visited 30 countries, flying 354,000 miles in the process - the equivalent of more than 14 times round the earth.

But for this trip, he's paying almost nothing to take in Mexico, Nicaragua, Trinidad, St. Lucia, Grenada, Germany, Czech Republic, Ukraine, Bulgaria, Greece, Macedonia, Lithuania and Finland. All it will cost him is a few airport taxes, each under $20.

After Keyes' friends kept asking him how he did it, he wrote two ebooks: How To Fly For Free and How To Find Cheap Flights. They explain everything from how to get yourself bumped from a flight - and compensated - to how to find mistake fares. He recommends being free with complaints, and keeping careful tabs on your points.

For those of us that don't have his dedication, Keyes recommends scouring travel websites for cheap deals and keeping an open mind.

"If your ultimate goal is to be able to find as cheap a flight as possible and go somewhere cool for not much money then starting with an open, blank slate and going wherever there's a cheap flight right now is going to be your best bet," he says.

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