The worst is yet to come

https://backpack.tf/item/7957340614

Sale 1) ?

https://backpack.tf/profiles/76561198816039340#!/compare/1564185600/1564272000

Sale 2) Sold + ~3 Keys of Items + 1 Key for a Circling TF Logo Deep Cover Operator

https://backpack.tf/profiles/76561198064816417#!/compare/1566000000/1566086400

This should be used to drop the DCO.

Sale 3) Sold for a Steaming Neckwear Headwear (19.5 Keys)

https://backpack.tf/profiles/76561198140128839#!/compare/1566172800/1566259200

https://backpack.tf/profiles/76561198164315915#!/compare/1566172800/1566259200

Rounds to 20 Keys

Neckwear Mini

https://backpack.tf/profiles/76561197996095002#!/compare/1566086400/1566172800 - Sold for a Miami Nights A Hat to Kill For (26.5 Keys)

https://imgur.com/a/8W2hry0 - The Hat to Kill For sale is capped by the Buyout of 23 Keys

https://backpack.tf/profiles/76561198267189538#!/compare/1564704000/1564790400 - Sold + 7 Keys for a Blizzardy Storm A Modest Pile of Hat

https://marketplace.tf/items/tf2/30307;5;u36 - Sold for $29.99 when Keys were ~$1.83 each

https://marketplace.tf/items/tf2/5021;6

29.99 / 1.83 = 16.39, which rounds to 16 Keys

Taking 16 - 23, which averages to 19.5 Keys for the Neckwear

Miami Nights A Hat to Kill For Micro

https://backpack.tf/profiles/76561197996095002#!/compare/1566777600/1566864000 - Sold for 25 Keys

https://backpack.tf/profiles/76561198335791307#!/compare/1559865600/1559952000 - Sold for 29 Keys

https://backpack.tf/profiles/76561198114379995#!/compare/1563667200/1563926400 - Sold for 27 Keys

https://imgur.com/a/XPaGkWK - Sellers at 24 Keys (4 Days), 25 Keys (5 Days), and 27 Keys (4 Hours)

Sale 4) Sold + ~2 Keys of Items for a Disco Beat Down Warhood (16 Keys)

https://backpack.tf/profiles/76561198164315915#!/compare/1566259200/1566432000

https://backpack.tf/profiles/76561198203697487#!/compare/1566172800/1566259200

16 - 2 = 14 Keys

Sale 5) Sold for a Cool FT Blue Mew SMG (14.5 Keys)

https://backpack.tf/profiles/76561198203697487#!/compare/1566345600/1566432000

https://backpack.tf/profiles/76561198189381361#!/compare/1566345600/1566432000

Rounds to 15 Keys

SMG Mini

https://backpack.tf/suggestion/5d6835786780726a7c38afa4 - 14.5 Keys

Sale 6) Sold + 4 Keys + ~0.5 Keys of Items for a Stormy Storm Charmer's Chapeau

https://backpack.tf/profiles/76561198189381361#!/compare/1566864000/1566950400

Using for the Charmer's.

Sale 7) Sold for a Miami Nights Climbing Commander (19 Keys)

https://backpack.tf/profiles/76561198153536726#!/compare/1566864000/1566950400

https://backpack.tf/profiles/76561198045999385#!/compare/1566864000/1566950400

Sale 8) Quicksold for 14 Keys

https://backpack.tf/profiles/76561198045999385#!/compare/1566950400/1567036800

https://backpack.tf/profiles/76561198082602429#!/compare/1566950400/1567036800

https://imgur.com/a/hNEzCGT - Young Seller at 20 Keys, Buyers at 12 Keys

https://backpack.tf/item/7957340614

https://backpack.tf/u/76561198342161127

https://backpack.tf/u/76561198002757046

Calling 14 low as 1 of the 2 sales was a quicksell and 14 is relatively close to the Buyers at 12. Using them to support 15 being the low end.