A nice, warm sack.

https://backpack.tf/item/4638674807

Sale 1) Sold for 15 Keys + Orbiting Planets Bloke's Bucket Hat (9.25 Keys)

https://backpack.tf/profiles/76561198071983249#!/compare/1521331200/1521676800

Low Outlier, but supports a drop.

Bloke's Mini

https://backpack.tf/suggestion/5b060d1d44325a02763180ce - 9.25 Keys

https://backpack.tf/item/6552170249

Sale 2) Can't tell how many Keys the Sack sold for, but I doubt it's higher than 25, since the bot Purple sold the Sack to sold the Sack for 25 Keys.

https://backpack.tf/profiles/76561198073553007#!/compare/1520899200/1520985600

Sale 3) Sold for 25 Keys

https://backpack.tf/profiles/76561198310144372#!/compare/1520985600/1521072000

Sale 4) Sold for a Starstorm Slumber Towering Pillar of Hats (30 Keys) + 1 Key + 9 Refined

https://backpack.tf/profiles/76561198035458322#!/compare/1521417600/1521504000

High Outlier.

Pillar Mini

https://backpack.tf/suggestion/5b06231a44325a095211d039 - 30 Keys

Sale 5) Sold for 26 Keys + 22.66 Refined

https://backpack.tf/profiles/76561198126693824#!/compare/1522368000/1522454400

Rounds to 27 Keys

Excluding the first sale because it rounds to 24 Keys, which is countered by these Buyers at 24 and 24.73 Keys ---> https://imgur.com/a/vmczW5R

The sale at 31 Keys is high because of the 1 Month Unsold at 28 Keys in the image above.