I found the actual letter from the SecDef:
Bottom line: DoD commits to building 57 specific miles, but the price is not specified.
SecDef made up to $1 billion immediately available, which should conservatively be more than enough, so contracting can confidently go ahead. They will conduct a bidding process to get an actual contract price, but bidding does not start until the Government Contracting Officer has the money in hand.
The memo does say that the barrier will include a pretty full suite of bells and whistles (Patrol road, stadium lighting with grid electric power, cameras and special detection systems/alarms).
I’d expect the actual contract prices to be more like $10 million per mile, and the remainder will be applied to other new segments in coming months.
Thanks