Black market

Nardole remarked that he would start a black market if there was more than three people in the room. (TV: The Doctor Falls)

In 1941, upon seeing the large quantities of food on the Lloyd family's table, Ernie remarked that it's must be from the black market, as "you couldn't get this off coupons", much to Nancy scolding him and assigning him with the washing up. (TV: The Empty Child)

In Pete's World, Jackie Tyler claimed that here birthday parties hosted "plenty of black market whisky". (TV: Rise of the Cybermen)

There was a black market selling alien species on Earth in the 21st century. John Harrison paid millions for a group of Skullion slaves who had crash landed in Central Asia. They were brought across Europe and then across the English Channel. (TV: The Man Who Never Was)

Bloorm Vungah Bart Slitheen, Dax Fex Fize Slitheen and Korst Gogg Thek Lutiven-Day Slitheen were planning to sell Luke Smith's telekinetic energy on the Energies Black Market on Antara IV, but couldn't fulfil their plans because Luke escaped. (PROSE: The Lost Boy)

The Order of the Custodians found that MDZ Research had been buying up any non-terrestrial weaponry on the black market. This included a Dalek gunstick which was recovered by a reconnaisance scout on 1 January 2019. (TV: Resolution)