Congressional Budget Office Cost Estimate: S. 456, Gang Abatement and Prevention Act of 2007 [open pdf - 21KB]
From the Summary: "S. 456 would authorize the appropriation of $849 million over the 2008-2012 period, nearly $170 million annually, for Department of Justice (DOJ) programs to investigate and prosecute criminal street gangs and to prevent gang activity. In addition, CBO [Congressional Budget Office] estimates that the bill would authorize the appropriation of about $550 million over the 2008-2012 period for programs to protect witnesses of crimes and for other crime-prevention activities. The bill also would establish new federal offenses and increase penalties for criminal activities committed by street gangs. Assuming appropriation of the necessary amounts, CBO estimates that implementing S. 456 would cost $1.1 billion over the 2008-2012 period. The bill could affect direct spending and revenues, but CBO estimates that any such effects would not be significant."
Congressional Budget Office: https://www.cbo.gov/