According to ASA, an ADSB ground station costs between $100,000 and $400,000 (compared to a RADAR system at $1 million to $4 million)
https://www.icao.int/Meetings/AMC/MA...SITF4/sp01.pdf
IG reports on FAA and ADSB:
FAA plans to spend approximately $1.7 billion on ADS-B through 2014, and an additional $1 billion between 2014 and 2020.
The final cost and timeline needed to fully implement ADS-B—and achieve the extent of its benefits—remain uncertain. FAA currently estimates the cost of the program (through 2035) to be $4.5 billion, an increase of $400 million from original estimates.
FAA has deployed the ADS-B ground infrastructure, but the ability for controllers and pilots to use ADS-B information throughout the NAS remains years away. Notably, FAA has yet to resolve significant hazards identified during operational testing or conduct more rigorous testing of the entire system to determine whether all ADS-B elements will perform as expected. As a result, FAA has not authorized the exclusive use of ADS-B information to manage air traffic across the NAS. Further, the Agency’s system for monitoring the performance of the ADS-B signal remains under development.
ADS-B BENEFITS ARE LIMITED DUE TO A LACK OF ADVANCED CAPABILITIES AND DELAYS IN USER EQUIPAGE Federal Aviation Administration Report Number: AV-2014-105 Date Issued: September 11, 2014
Another pretty scathing report on ADSB.
https://www.ignet.gov/sites/default/...rd%20Letko.pdf