Buying off land?
Since Alaska no country is stupid enough to sell land.

People are mistaken when they hear somebody has bought an island in Greece.
They bought that island like you buy a flat, the country that owns that land is still Greece and they can do whatever they want with it if they decide to nationalize.

And let's be reasonable.
Let's say you achieve independence. You become prosperous. What will happen next?
You are going to get invaded by your neighbors and crushed in a matter of hours.

And nobody will save you because it will serve as a lesson from the governments to utopians.