Auction
An auction was a method of bartering in which the product was bid for by the audience with the highest bit winning.
In July 64, in Rome, Barbara Wright was sold by Sevcheria to Tavius for 10,000 sesterces after a slave auction. (TV: "All Roads Lead to Rome")
Throughout the 1950s, alien artefacts were stolen by members of Torchwood Three and sold at auctions in Cardiff. Jack Harkness eventually destroyed the demand for these auctions by flooding the market with fake artefacts. (PROSE: The Beauty of Our Weapons)
Jamie McCrimmon was kidnapped by the Voraxx, who brought him on board their slaver ship and intended to sell him in a slave auction. He was rescued by the Second Doctor and Zoe Heriot. (COMIC: Bazaar Adventures)
The Dalek nicknamed "Metaltron" had been bought in a private auction by Henry Van Statten for his collection. (TV: Dalek, PROSE: Object Auction, The Secret Lives of Monsters, Dalek, et al.)
In the Unthinkable City, specifically created on 21st century Earth, an auction to sell the Relic (the Doctor's corpse) was set up by Qixotl. (PROSE: Alien Bodies)