Item 1: https://backpack.tf/item/7957531672

Sale 1:

https://backpack.tf/profiles/76561198311498888#!/compare/1763683200/1763769600

https://backpack.tf/profiles/76561198843960450#!/compare/1763683200/1763769600

15 keys

Sale 2:

https://backpack.tf/profiles/76561198843960450#!/compare/1763683200/1763769600

https://backpack.tf/profiles/76561198192023081#!/compare/1763596800/1763769600

Bulk

Sale 3:

https://backpack.tf/profiles/76561198192023081#!/compare/1763769600/1763942400

https://backpack.tf/profiles/76561198060734925#!/compare/1763683200/1763769600

Untrace

Sale 4:

https://backpack.tf/profiles/76561198060734925#!/compare/1764547200/1764806400

https://backpack.tf/profiles/76561198077555267#!/compare/1764547200/1764806400

20 keys

Sales:

15, 20

Sellers:

BPTF - https://imgur.com/oblJvEQ none

MPTF - https://marketplace.tf/items/tf2/30057;5;u8 none

STN - https://stntrading.eu/item/tf2/Unusual+Haunted+Ghosts+Bolted+Birdcage non but there's a buy order at 17 keys 4.33 ref

SCM - https://steamcommunity.com/market/listings/440/Unusual%20Bolted%20Birdcage?filter=Haunted+Ghosts https://imgur.com/v2H0aIs none

Despite the buy order at 17 keys, the sale at 15, going by the history, seems to have taken nearly a month to sell, so I don't think it's necessarily low. Buyers on BPTF are only at around 14 keys.

Going with 15-20 keys for now but if preferred I'll happily resuggest at 20 keys flat

Buyers on BPTF are now at ~16 keys and STN has settled a buy order at ~16 keys too, going to go with 20 flat