Sale 1:

Sold for 11 keys + 22 ref

Seller: https://backpack.tf/profiles/76561198304138933#!/compare/1525046400/1525132800

Buyer: https://backpack.tf/profiles/76561198305596862#!/compare/1525046400/1525132800

Bot.tf confirms: https://i.imgur.com/MjAw3Ff.png

X = 12

Sale 2:

Sold for 11 keys + 22 ref

Seller: https://backpack.tf/profiles/76561198304138933#!/compare/1524182400/1524268800

Buyer: https://backpack.tf/profiles/76561198241802314#!/compare/1524182400/1524268800

Bot.tf confirms: https://i.imgur.com/MjAw3Ff.png

X = 12

Sale 3:

Sold for Aussie Spec. KS SMG (~6.6) + 4 keys

Seller: https://backpack.tf/profiles/76561198241802314#!/compare/1524787200/1524960000

Buyer: https://backpack.tf/profiles/76561198257103753#!/compare/1524873600/1524960000

X = 11

Sale 4:

Sold to a bot for 10 keys + 7 ref

https://backpack.tf/item/897066128 - Seller can’t be identified, they bought from scrap and immediately sold to the bot.

Buyer: https://backpack.tf/profiles/76561198304138933#!/compare/1523059200/1523145600

Bot.tf confirms: https://i.imgur.com/MjAw3Ff.png

X = 10

Sale 5:

Sold to a bot for 10 keys + 7 ref

https://backpack.tf/item/749658434 - Seller can’t be identified, histories show it came from a totally legit OPSKINS bot.

https://backpack.tf/profiles/76561198304138933#!/compare/1524960000/1525046400

Bot.tf confirms: https://i.imgur.com/MjAw3Ff.png

X = 10

Sale 6:

Sold for Steaming Strontium Stove-Pipe (Mini at 9 below) + 1 key

http://www.tf2outpost.com/trade/29612338 - No B/O

Seller: https://backpack.tf/profiles/76561198084537490#!/compare/1523059200/1523145600

Buyer: https://backpack.tf/profiles/76561198137532237#!/compare/1522972800/1523145600

X = 10

Sale 7:

Sold for fuck-all

Seller: https://backpack.tf/profiles/76561198286992394#!/compare/1523059200/1523145600

Buyer: https://backpack.tf/profiles/76561198084537490#!/compare/1522972800/1523059200

X = fuck-all

Steaming Strontium Mini:

No usable sales, using sellers.

https://i.imgur.com/KJULQhn.png

https://backpack.tf/item/1884967857 - ~8.8 keys, 26 days

https://backpack.tf/item/3468892166 - 10 keys, 2 months

Going with 9.

Sellers:

12 keys:

https://i.imgur.com/snFZ1Om.png

https://backpack.tf/item/897066128

13 keys:

https://i.imgur.com/0weN2Jf.png

https://backpack.tf/item/490292735

https://backpack.tf/item/890887873

Sales at:

10 (3x)

11

12 (2x)

10 sold to buy orders no doubt influenced by this suggestion, but 10 is a “common trading point”, so I’ll be using that as the low-end, even with buy orders at 10.

Going with 10-12.