While there are programs that are covered by state funding and federal grants as well as grants for different studies associated with addiction, few require no investment from the client.Even when drug rehab is a mandate of the court, and the state basically covers the cost of  treatment, there are still costs to the individual. In some cases, court fees or a reimbursement for drug addiction treatment services may apply. When drug rehab is residential and covered by the state, clients are usually required to hand over the government subsidies they receive through cash aid and food stamps.