Crocodile-Infested Waters

http://backpack.tf/item/1701720423

Sale 1) Sold + ~2 Keys of Items for a Catastrophic Companions (21.5 Keys)

http://backpack.tf/profiles/76561198120499671#!/compare/1479945600/1480032000

21.5 - 2 = 19.5, which rounds to 20 Keys

http://backpack.tf/item/1889738459

Sale 2) Sold for an Australium Black Box (14 Keys) + 3 Keys

http://backpack.tf/profiles/76561198093204373#!/compare/1481155200/1481241600 - Buyer's Backpack

14 + 3 = 17 Keys

Sale 3) Sold for a Smoking Soldier's Slope Scopers (17 Keys)

http://backpack.tf/profiles/76561198093204373#!/compare/1481241600/1481414400

Scopers Mini

http://backpack.tf/profiles/76561198093204373#!/compare/1481500800/1481673600 - Sold + ~2 Keys of Items for a Strange Festive Pro KS Rocket (~19 Keys)

http://www.tf2outpost.com/trade/28645909 - Seller at 16 Keys

http://www.tf2outpost.com/trade/28646773 - 1 Week Unsold at 18 Keys

http://www.tf2outpost.com/trade/28648441 - 1 Week Unsold at 18 Keys