Sale 1:

Sold for Dead Presidents Samur-Eye (Mini at 18 below)

No outpost

Seller: http://backpack.tf/profiles/76561198049566072#!/compare/1483660800/1483747200

Buyer: http://backpack.tf/profiles/76561198115993868#!/compare/1482537600/1483747200

X = 18

Sale 2: (Dupe)

Sold for Orbiting Fire L’Inspecteur + Neutron Star Spirit of the Bombing Past

No outpost

Seller: http://backpack.tf/profiles/76561198125791160#!/compare/1483574400/1483660800

Buyer: http://backpack.tf/profiles/76561198087397149#!/compare/1483488000/1483660800

This sale will end up being around 25 keys, which will look like a bit of an outlier.

Sale 3: (Dupe)

Sold for 13 keys

No outpost

Seller: http://backpack.tf/profiles/76561198087397149#!/compare/1484265600/1484352000

Buyer: http://backpack.tf/profiles/76561198041822925#!/compare/1484006400/1484352000

X = 13

Dead Presidents Samur-Eye Mini:

http://backpack.tf/suggestion/58aadc97c44045173c1fa1b9

Sellers:

20 keys:

http://i.imgur.com/21LsW7s.png - 1 month

http://backpack.tf/u/76561198041822925

Sales at:

13

18

~25

Sale at 13 seems incredibly low, especially with a buyer at 14 here:

http://www.tf2outpost.com/trade/28768723

Excluding 13.

Sale at ~25 will be excluded, due to the month-old seller at 20 keys.

Going with 18 flat.