Sale 1:

Sold for 12 keys

http://www.tf2outpost.com/trade/29304138 - B/O of 12

Seller: https://backpack.tf/profiles/76561198232041512#!/compare/1501372800/1501459200

Buyer: https://backpack.tf/profiles/76561198331279752#!/compare/1501200000/1501459200

X = 12

Sale 2:

Sold for ~11 keys in taunts and stuff

No outpost

Seller: https://backpack.tf/profiles/76561197969049043#!/compare/1500940800/1501027200

Buyer: https://backpack.tf/profiles/76561198121694613#!/compare/1500681600/1501027200

X = 11

Sale 3:

Sold with Botkiller Killstreak Knife (~1) for Steaming Gatsby

Seller: https://backpack.tf/profiles/76561198121694613#!/compare/1504310400/1504396800

Buyer: https://backpack.tf/profiles/76561198011321852#!/compare/1504310400/1504396800

Should be used on the Gatsby.

Sale 4:

Sold for Green Confetti Backbiter’s Billycock

http://www.tf2outpost.com/trade/29322843 - B/O of 14

Seller: https://backpack.tf/profiles/76561198142921440#!/compare/1501891200/1502064000

Buyer: https://backpack.tf/profiles/76561198188401374#!/compare/1501718400/1502064000

Can be used on the Billycock.

Sellers:

11.5 keys:

https://i.imgur.com/rh7h3ag.png - 13 days

13 keys:

https://i.imgur.com/qu0tD1a.png - 24 days

Sales at:

11

12

Going with 11-12.