The flights to get to certain areas are expensive, maybe $500, but one you're there you can travel to neighbouring countries tries for less then $100. That's on a plane, but you can get from Cambodia to Thailand, for example, on a decent sleeper bus for less then $20.
And when you're in a lot of South East Asian countries, the cost of living is very cheap. $2 for a taxi, $1 for a cheap meal, $2 for a pack of smokes etc.
That's countered slightly by the expensive countries though, so you don't want to be staying there too long. Take Australia for example... $11 for a beer, $10 for a cheap meal, $25 for a cheap pack of smokes... only mad people would live there.
But still, on average, the world is a pretty affordable place if you have a 'western style' income every month.
I appreciate that not everyone gets a 'western style' income, but the great thing about digital sales is that your earning potential is only limited by the quality and commercial viability of your work... you're not held back by the average wages of the country you live in.