How North Korea Pays For Its Russian Oil

Slaves.

Pyongyang's oil imports increased from 62,000 dollars in 2001 to 4.4 million dollars last year.
An expert who lives in North Korea, anonymous for security reasons, said: "The city from where the oil is coming does not have its own energy resources. It exports oil to North Korea on behalf of the federal government of Moscow and in compensation receives labour instead of money due to North Korean incapability of making payments."

I checked my Palm Pilot and yes, it is the 21st century.