street value       
noun [ C usually singular, U ] uk/ˈstriːt ˌvæl.juː/ us/ˈstriːt ˌvæl.juː/
 (非法物品,尤指毒品的)街头黑市价格
the price that is paid for something illegal, especially a drug, by the person who uses it
  Customs officers discovered heroin with a street value of $6 million. 海关官员查获了黑市市值600万美元的海洛因。