SHOW ME YOUR WAR FACE

https://backpack.tf/item/267632531

Sale 1) Sold for a Sunbeams Stout Shako

https://backpack.tf/profiles/76561198073553007#!/compare/1502755200/1502841600

http://www.tf2outpost.com/trade/29327626 - Capped by the Buyout of 40 Keys

https://backpack.tf/item/314843487

Sale 2) Sold for a Duped Haunted Ghosts Engineer's Cap + 4 Keys + 7 Refined

https://backpack.tf/profiles/76561198262288177#!/compare/1497052800/1497398400

Fits in the range.

Sale 3) Sold for a Circling Peace Sign Wraith Wrap (42 Keys) + 1 Key

https://backpack.tf/profiles/76561198161053005#!/compare/1497398400/1497571200

http://www.tf2outpost.com/trade/29228534 - Capped by the Buyout of 36 Keys

Sale 4) Sold for a Searing Plasma Armored Authority + Orbiting Planets Warhood + ~1 Key of Items

https://backpack.tf/profiles/76561197996095002#!/compare/1499212800/1499299200

High Outlier.

Sale 5) Sold for a Duped Circling TF Logo Large Luchadore + ~0.6 Keys of Items

https://backpack.tf/profiles/76561197980036614#!/compare/1499299200/1499385600

Fits in the range.

Sale 6) Sold for a Tesla Coil A Hat to Kill For + ~3 Keys of Items

https://backpack.tf/profiles/76561198061489334#!/compare/1501372800/1501459200

http://www.tf2outpost.com/trade/29301184 - Capped by the Buyout of 40 Keys

Sale 7) Sold + 3 Keys for a Duped Green Energy Safe'n'Sound

https://backpack.tf/profiles/76561198072087574#!/compare/1501459200/1501545600

High Outlier.

Sale 8) Sold + 7 Keys for a Blizzardy Storm Bonk Boy (39 Keys)

https://backpack.tf/profiles/76561198104168501#!/compare/1501459200/1501545600 - Seller's Backpack

https://backpack.tf/profiles/76561198267189538#!/compare/1501459200/1501545600 - Buyer's Backpack

39 - 7 = 32 Keys

Sale 9) Sold for 29 Keys + ~1 Key of Items

https://backpack.tf/profiles/76561198095862827#!/compare/1503878400/1503964800

29 + 1 = 30 Keys

Sale 10) Sold for a Cloud 9 Dread Hiding Hood (37 Keys) + Professional Killstreak Australium Blutsauger (~9 Keys) + 6 Keys + 6 Refined

https://backpack.tf/profiles/76561198126114757#!/compare/1503878400/1503964800

High Outlier.

Going 30 - 40, using the Engineer's Cap and Large Luchadore sales to support 40 Keys.

I'm ignoring the seller at 29 Keys because the listing is young.

Also, these sellers make sales 4, 7, and 10 high outliers: http://imgur.com/a/0dgsg