Sale 1:

Sold for Flies Brigade Helm

http://www.tf2outpost.com/trade/28187609 - B/O of 11

Seller: http://backpack.tf/profiles/76561198234515248#!/compare/1463875200/1463961600

Buyer: http://backpack.tf/profiles/76561198203537236#!/compare/1463875200/1463961600

X = 11 (Capped by B/O)

Sale 2:

Sold for 11 keys

http://www.tf2outpost.com/trade/28027896 - B/O of 11

Seller: http://backpack.tf/profiles/76561198068658521#!/compare/1459468800/1459641600

Buyer: http://backpack.tf/profiles/76561198174453105#!/compare/1459555200/1459814400

X = 11

Sale 3:

Sold for 10 keys (and a scrap)

No outpost

Seller: http://backpack.tf/profiles/76561198068180717#!/compare/1462060800/1462147200

Buyer: http://backpack.tf/profiles/76561198037270193#!/compare/1462060800/1462233600

X = 10

Sale 4: (Dupe)

Quicksold for 9 keys

http://www.tf2outpost.com/trade/28206326 - B/O of 9

Seller: http://backpack.tf/profiles/76561198135927262#!/compare/1464220800/1464393600

Buyer: http://backpack.tf/profiles/76561198117597416#!/compare/1464307200/1464393600

X = 9

Buyer at 10 keys:

http://www.tf2outpost.com/trade/27934308

Sellers:

12 keys:

http://www.tf2outpost.com/trade/28252850 - 1 week

13 keys:

http://www.tf2outpost.com/trade/28134884 - 1 month

Sales at:

9

10

11

11

Sales at 10 and lower are too low, due to the buyer

2 sales at 11

Going with 11 flat