All credits to the original suggestor surz for the sales and Xergoyf for the maketplace sales

Sales

Sold for 11 keys + 55 refined

https://backpack.tf/profiles/76561198841279602#!/compare/1606003200/1606089600

https://backpack.tf/profiles/76561198140185303#!/compare/1606003200/1606176000

Probably not the complete sale, considering the seller purchased for 23.

Sold for 23 keys~

https://backpack.tf/profiles/76561198170427507#!/compare/1593734400/1606003200

https://backpack.tf/profiles/76561198841279602#!/compare/1605916800/1606003200

Untrace

https://backpack.tf/profiles/76561198002186909#!/compare/1604707200/1604793600

https://backpack.tf/profiles/76561198070680922#!/compare/1603411200/1605052800

Sold for 18 keys

https://backpack.tf/profiles/76561198041391488#!/compare/1601164800/1603324800

https://backpack.tf/profiles/76561198358234951#!/compare/1603238400/1603324800

Transfers between alt and main

https://backpack.tf/item/2444782721

Sold with 3 keys for Vexed Volcanics Seared Sorcerer

https://backpack.tf/profiles/76561198102211716#!/compare/1602115200/1602201600

https://backpack.tf/profiles/76561199021670907#!/compare/1597363200/1602201600

Dang, buyers are at like 42~ for the Sorcerer, ripp :(

Sold for Arcane Assistance Taunt: The Skating Scorcher

https://backpack.tf/profiles/76561198048478229#!/compare/1601510400/1601942400

https://backpack.tf/profiles/76561198102211716#!/compare/1601424000/1601769600

The scorcher has sellers between 15 and 20, which is less than buyers for the Bicorne, excluding.

Marketplace sales

https://marketplace.tf/items/tf2/607;5;u62

$49.99 / $1.85 = 27.02 keys

$10 / $1.81 = 5.52 keys

$49.99 / $1.80 = 27.77 keys

$49.99 / $1.80 = 27.77 keys

Classifieds

https://gyazo.com/62ecdd1354fc98cf40f5385c747649e3

Conclusion : 23-28 as suggested by Xergoyf

https://backpack.tf/suggestion/5feb0b46c0bd1d050249719e