Travel Hacking is gaming the system, using completely fair, ethical and legal ways to minimise your travel costs so you can have your amazing dream vacation on a budget.
The most effective way to do this is by racking up frequent flyer miles. Most people don't realise that you can earn more frequent flyer miles on the ground than you do by actually flying. Airlines have partnerships with each other, with hotels, car rental companies, credit cards, and more. I even earned about 300 miles yesterday by doing some free online surveys.
The credit card thing is risky if you don't know what you're doing. I recommend reading this book, and joining the Travel Hacking Cartel. If you use my referral link, we each get some miles for free!
I'm just starting out in this, but once I've scoped it out and hit 10000 miles I'll write a more in-depth post about how to do it, specifically while living in Korea.
In the meantime, join the cartel and read the book to get started. You get a free 14-day trial for just $1.