Item 1:

https://backpack.tf/item/16313926049

Sale 1:

https://backpack.tf/profiles/76561199059632349#!/compare/1767744000/1767830400

https://backpack.tf/profiles/76561199164971297#!/compare/1767744000/1767830400

Sold for 10 keys pure (ID 16602140965)

Sale 2:

https://backpack.tf/profiles/76561198991301039#!/compare/1763596800/1765929600

https://backpack.tf/profiles/76561199059632349#!/compare/1763596800/1767139200

Dumped to a bot, untrace

Sale 3:

https://backpack.tf/profiles/76561199099462094#!/compare/1763424000/1763596800

https://backpack.tf/profiles/76561198991301039#!/compare/1762646400/1763596800

Untrace

Item 2:

https://backpack.tf/item/9119626084

Sale 4:

https://backpack.tf/profiles/76561198145331385#!/compare/1765929600/1766016000

https://backpack.tf/profiles/76561199177132803#!/compare/1765929600/1766016000

Moved between owner and bot

Sale 5:

https://backpack.tf/profiles/76561199177132803#!/compare/1767484800/1767571200

https://backpack.tf/profiles/76561198204701269#!/compare/1767052800/1767571200

Sold for 10 keys pure

Sale 6:

https://backpack.tf/profiles/76561198204701269#!/compare/1767571200/1767657600

https://backpack.tf/profiles/76561198020399100#!/compare/1767571200/1767744000

Added 5 keys for a Strange Australium Frontier Justice (~18)

= 13

Item 3:

https://backpack.tf/item/16382091328

Sale 7:

https://backpack.tf/profiles/76561198986850781#!/compare/1762473600/1762560000

https://backpack.tf/profiles/76561199186541168#!/compare/1762473600/1762560000

Dumped to a buy order, looks like 9

Item 4:

https://backpack.tf/item/3023288862

Listed on mannco

//

Sellers:

BPTF - https://imgur.com/a/eTC95nF - 3 @ 10 keys

MPTF - https://marketplace.tf/items/tf2/30008;5;u36

STN - https://stntrading.eu/item/tf2/Unusual+Steaming+Towering+Titanium+Pillar+of+Hats - None

SCM - https://steamcommunity.com/market/listings/440/Unusual%20Towering%20Titanium%20Pillar%20of%20Hats?filter=Steaming - https://imgur.com/a/fYI1wfU - 1 @ $54.09AUD (~16 keys)

Sale(s):

10, 10, 13, 9

13 is too high due to unsolds and keeping 9 out of the range due to it being very close to buy orders.

Going with 10 keys flat

(Credits Shuffle)