If you chase the links you end up on the Georgia Tech site about it: http://www.omscs.gatech.edu/faq.

  We’re not yet ready to announce a specific program cost, 
  but the plan is to offer the Georgia Tech OMS CS for a 
  total cost of under $7,000—a fraction of the cost of 
  Georgia Tech’s on-campus program and even less than that 
  of comparable private universities.

All the content will be free to everybody, but you have to apply to Georgia Tech and pay if you want the actual degree.

You also have to have a Bachelor's degree, which is a disappointment for me. I left college before completing my BS in CS, and I'd love to be in this program, but I wouldn't be admitted.

[disclosure: my wife works in the Georgia Tech Professional Education group, which is how I heard about this]