According to Kramer, the average Station Exchange participant spent more than $70 during the system's first 30 days, and to one observer, that number is the most impressive to come out of the experiment.
Sony takes a 10 percent commission from each sale, and charges a $1 listing fee for currency or other items and a $10 listing fee for characters, according to Kramer. But he wouldn't say how much money Sony is making overall with the new service.

"If you think about it, if you had an industry with 5 million active people (as there are in online games), and they spent $70 a person per month, that would be a $4 billion-a-year industry," said Ed Castronova, an expert on the economies of MMOs and a professor of telecommunications at the University of Indiana.