Sale 1:

Sold with ~5 keys in items for Aussie Scattergun (23)

No outpost

Seller: https://backpack.tf/profiles/76561198078782165#!/compare/1497916800/1498089600

Buyer: https://backpack.tf/profiles/76561198107177604#!/compare/1498003200/1498089600

X = 18

Sale 2:

Sold for $36.99 on Marketplace.tf

https://marketplace.tf/items/152;5;u36

https://backpack.tf/item/4908605787

36.99/2.05 = ~18

X = 18

Sale 3:

Sold for Smoking Sergeant’s Drill Hat (Suggestion at 15) + < 2.5 keys in items

http://www.tf2outpost.com/trade/29197234 – Deleted B/O, nothing cached

Seller: https://backpack.tf/profiles/76561198114402400#!/compare/1497571200/1497657600

Buyer: https://backpack.tf/profiles/76561198258087983#!/compare/1497571200/1497657600

X = 17

Sale 4:

Sold with a key for Pro. KS Aussie Ambassador (16)

No outpost

Seller: https://backpack.tf/profiles/76561198073955220#!/compare/1498003200/1498089600

Buyer: https://backpack.tf/profiles/76561198078782165#!/compare/1497916800/1498089600

X = 15

Smoking Sergeant’s Drill Hat:

https://backpack.tf/suggestion/59a9045ecf6c75493c5a2c43

Sellers:

http://i.imgur.com/1J0buSA.png - 2 months

Sales at:

15

17

18 (2x)

Going with 15-18.