Shuffle Spy:

https://backpack.tf/profiles/76561198078777084#!/compare/1642464000/1642550400 - Bulk

https://backpack.tf/item/10663507936 - Dumped to a bot for ~13 Keys

https://gladiator.tf/sales?item=Massed%20Flies%20Thousand-Yard%20Stare&at=2022-02-04T07:41:21.927Z

https://gladiator.tf/listings/61fcd6f54add58816c486119 - Now listed for 16 Keys

https://steamcommunity.com/market/listings/440/Unusual%20Thousand-Yard%20Stare?filter=flies - Sellers at 15 Keys

25 is too high and there isn't actually proof of the 14 Key sale (it got dumped elsewhere immediately), so a range of 15 - 16 would work here.

Credits to Strange:

https://marketplace.tf/items/tf2/31200;5;u12

https://backpack.tf/item/10371176946

$29.99 / $1.86 = 16.12 keys

https://backpack.tf/item/10663507936

25 keys:

https://backpack.tf/profiles/76561198418740133#!/compare/1640304000/1640563200

https://backpack.tf/profiles/76561198040768114#!/compare/1640217600/1640563200

https://backpack.tf/item/10663507936

https://backpack.tf/profiles/76561198165373557#!/compare/1634083200/1634515200

https://backpack.tf/profiles/76561198418740133#!/compare/1634428800/1634515200

bulk

https://backpack.tf/item/10661985155

https://backpack.tf/profiles/76561199025410447#!/compare/1632355200/1632700800

https://backpack.tf/profiles/76561198311498888#!/compare/1632441600/1632700800

untrace

https://backpack.tf/profiles/76561198311498888#!/compare/1637193600/1637280000

https://gyazo.com/9536edcbad8eb3e3329de69c03c06225

this looks to be ~14k

https://backpack.tf/profiles/76561198377253480#!/compare/1637280000/1638835200

https://loot.farm/

https://gyazo.com/a72697d269e61de93b028ace71dc85b3 - loot.farm seems to sell unu. thousand yard stares for ~$38 regardless of effect (low-tiers), site values keys at $2.42, making this a ~16k sale in all likelihood