Strategy Page
In late 2017 Australia ordered another 3,900 American SDB (Small Diameter Bomb also known as GBU-39) for $209,000 each (including training and maintenance accessories and support). This order is for the SDB II (GBU-39B) for its F-35 fighters. In early 2016 Australia ordered 2,950 of the earlier model (SDB I) that can only hit stationary targets. These cost $131,000 each. The 130 kg (285 pound) SDB entered service in 2006 and so far over 20,000 have been ordered or delivered, most by the U.S. Air Force.
https://www.strategypage.com/htmw/htairw/articles/20171025.aspx
