Pumpkin Stout

https://backpack.tf/item/1204080820

Sale 1) Sold for 19 Keys

https://backpack.tf/profiles/76561198112279227#!/compare/1505865600/1505952000

Sale 2) Sold + ~4 Keys of Items for a Steaming Coldsnap Cap (25 Keys)

https://backpack.tf/profiles/76561198036385359#!/compare/1512259200/1512345600 - Seller's Backpack

https://backpack.tf/profiles/76561198186301509#!/compare/1512086400/1512345600 - Buyer's Backpack

25 - 4 = 21 Keys

Sale 3) Sold for an Orbiting Planets Hat With No Name (16 Keys)

https://backpack.tf/profiles/76561198186301509#!/compare/1512086400/1512345600 - Seller's Backpack

https://backpack.tf/profiles/76561198074181346#!/compare/1512259200/1512345600 - Buyer's Backpack

Hat With No Name Mini

https://backpack.tf/suggestion/5a262dbdcf6c755f860a96c1 - 16 Keys

Calling 16 a low Outlier and taking a conservative drop to 19 - 21 Keys.