Cost of Mir

[ARD]

I was curious about a cost figure for the Mir space station I found.  Wikipedia cites the New York Times article from 2001 (http://www.nytimes.com/2001/03/24/science/24MIR.html) for a total lifetime cost to the Soviet Union/Russia of $4.2 billion.  Even adjusted for inflation twelve years later, that's not a lot, and to me, that seems almost suspiciously low--less than Skylab, according to The Space Review (http://www.thespacereview.com/article/1579/1), for a much longer operational life. 

So, my questions are:

Is it possible that the NY Times article refers exclusively to the cost paid by the Russian Federation, and not the Soviet Union's investment? 

Was any funding for Mir provided by other outside entities (like the United States, during Shuttle-Mir)? 

Is there any other reliable source on Mir's cost? 

If the $4.2 billion figure is correct for total lifetime costs (development, launch, and operations), how did the Russians manage to keep costs so low? 

[Jim]

If the $4.2 billion figure is correct for total lifetime costs (development, launch, and operations), how did the Russians manage to keep costs so low? 

Non market economy, Low wages for engineers and conscripted soldiers performing tasks at the launch site.