Sale 1:

Sold with a key and a cosmetic for a Max’s Head (~18.5)

Seller: https://backpack.tf/profiles/76561198253093948#!/compare/1534118400/1534204800

Buyer: https://backpack.tf/profiles/76561198240537922#!/compare/1533686400/1534204800

https://backpack.tf/item/6886334718

https://scrap.tf/auctions/38E0A5 - Credit to AJ

X = 17

Sale 2:

Sold for 15 keys

http://www.tf2outpost.com/trade/29722171 - B/O of 19

Seller: https://backpack.tf/profiles/76561198080179568#!/compare/1533945600/1534032000

Buyer: https://backpack.tf/profiles/76561198253093948#!/compare/1533945600/1534032000

https://backpack.tf/item/6886334718

X = 15

Sale 3:

Bulk for Kill-a-Watt Brotherhood of Arms

Seller: https://backpack.tf/profiles/76561198418244311#!/compare/1534118400/1534204800

Buyer: https://backpack.tf/profiles/76561198114782270#!/compare/1534118400/1534204800

https://backpack.tf/item/6886334718

Sale 4:

Bulk for Strange Stormy Merc’s Mohawk

Seller: https://backpack.tf/profiles/76561198114782270#!/compare/1534464000/1534550400

Buyer: https://backpack.tf/profiles/76561198024925599#!/compare/1534377600/1534550400

https://backpack.tf/item/6886334718

Sale 5:

Bulk for Poisoned Shadows Brotherhood of Arms

Seller: https://backpack.tf/profiles/76561198053747026#!/compare/1528848000/1528934400

Buyer: https://backpack.tf/profiles/76561198285887364#!/compare/1528848000/1528934400

https://backpack.tf/item/2304094563

Sellers:

https://i.imgur.com/tWfvqg7.png

https://backpack.tf/item/6997250332 - 17 keys

https://backpack.tf/item/6886334718 - 20 keys

https://backpack.tf/item/5726096414 - 27 keys

Sales at:

15

17

Considering the sale at 15 sold for a fair bit less than their B/O, and scrap.tf is currently paying 16+ for anything with a low-end of 23, I’d say this is a bit of an outlier.

https://i.imgur.com/prORa8W.png

https://backpack.tf/stats/Unusual/Data%20Mining%20Light/Tradable/Craftable/62

Going with 17 flat.