There were some discussions about the cost in the previous thread.
Here is an excerpt from an article
For now, the plan is for the cameras to be in three ballparks this year—Miller Park in Milwaukee, Target Field in Minnesota, and a second season at Citi Field—and every park in the league by 2015. Like PITCHf/x, it will be made available in near-realtime for broadcast and highlights.
The obvious question is how public the data will be, and MLBAM doesn't have definitive answers just yet. That can be read as the cookie jar slamming shut on this fantastic data, due to teams hoarding it so they can run proprietary evaluations for themselves. In actuality, it's more like the league not wanting to get ahead of itself. It will likely take a similar rollout to PITCHf/x, which made its way into the public domain back in 2006. Among concerns about how to make this stuff public, the issue of the sheer scale of the data has already cropped up. This will likely be a massive amount of data and take a massive amount of computational power to sort through—the SportVU data, for example, is incredibly heavy—so just the delivery mechanism could be a bottleneck, like you see with 4k TV content.