A few years ago, I started searching for the best ways to save money on airline flights.I wanted to see the world -- or at least the United States -- but I didn't have a bottomless budget. In the end, I found something surprising.

There is a group of people who are flying for free by using a strategy that is the complete opposite of what most people do. Here's how it works:

How to Fly for Free

It probably comes as no surprise to you that a great way to fly for cheap is by using frequent flyer miles. It's pretty simple: cash in your miles, get a free flight, travel for less.

At first, I assumed that you had to fly all the time to earn frequent flyer miles. They are called "frequent flyer" miles after all. As it turns out, that's the complete opposite of what is true. The best way to earn frequent flyer miles isn't by flying at all. It's by finding the best credit card deals for earning frequent flyer miles, free hotel stays, and rewards points.

Here's Your Bonus...

The credit card market is extremely competitive and very lucrative. As a result, credit card companies will hand out huge frequent flyer bonuses to get you to pick up their card.

A typical bonus for getting a new credit card is 25,000 frequent flyer miles. Occasionally, you can get as many as 100,000 frequent flyer miles just by signing up for a new card.

In case you're wondering, 100,000 frequent flyer miles is enough to get you a round-trip business class ticket from the U.S. to Europe. That's a value of about $5,000 for taking 10 minutes to fill out a credit card application.

Despite the huge payoff, I was still skeptical at first. How many cards could I apply for? Would this strategy hurt my credit score?

The rest is here:

Travel for Free: How Credit Card "Churners" Do It