"An additional cocaine-control dollar generates societal cost savings of 15 cents if used for source-country control, 32 cents if used for interdiction, and 52 cents if used for domestic enforcement. In contrast, the savings from treatment programs are larger than control costs: an additional cocaine-control dollar generates societal cost savings of $7.48 if used for treatment."

Source

Rydell, C.P. & Everingham, S.S., "Controlling Cocaine," Prepared for the Office of National Drug Control Policy and the United States Army (Santa Monica, CA: Drug Policy Research Center, RAND Corporation, 1994), p. 42.
http://www.rand.org/pubs/mono…