If you're referring to the “black market” as your friendly neighborhood drug dealer ( that's a joke) then it is available. At least where im from. There is the 10 MG pills and the liquid readily available around here. The 40 MG wafers are no longer available at the methadone clinics. read more
Methadone is available on the streets, but one reason why it might be harder to come by is that doctors very rarely prescribe it to anyone who isn't terminal. read more