Mini for the Cloud 9 Bonk Boy

Cloud 9 Lucky Shot

Sale 1

Sold for 24 keys

https://backpack.tf/profiles/76561198349886701#!/compare/1531612800/1531699200

https://backpack.tf/profiles/76561198132561543#!/compare/1531612800/1531699200

Sale 2

Sold with 37 keys for a Cloud 9 Bonk Boy (using there)

https://backpack.tf/profiles/76561198132561543#!/compare/1532649600/1532736000

https://backpack.tf/profiles/76561198179707937#!/compare/1532649600/1532736000

Sale 3

Sold for a Blizzardy Storm Tyrant's Helm (25) + 3 keys = 28 keys

https://backpack.tf/profiles/76561198021055079#!/compare/1531094400/1531180800

https://backpack.tf/profiles/76561198364735647#!/compare/1530835200/1531267200

Mini for the Tyrant's Helm

https://backpack.tf/suggestion/5b8ab9a0cf6c750ae22d9ced

Taking 25 keys

Sale 4

Bulk

https://backpack.tf/profiles/76561198074924284#!/compare/1531180800/1531267200

https://backpack.tf/profiles/76561198364735647#!/compare/1530835200/1531267200

Sale 5

Bulk with a C9 Bonk Boy (used there)

https://backpack.tf/profiles/76561198100722286#!/compare/1531785600/1531872000

https://backpack.tf/profiles/76561198095236132#!/compare/1531699200/1531785600

Sale 6

Sold for an Australium Rocket Launcher (32 keys)

https://backpack.tf/profiles/76561198095236132#!/compare/1532908800/1532995200

https://backpack.tf/profiles/76561198037509122#!/compare/1532908800/1532995200

Sale 7

Sold for 22 keys

https://backpack.tf/profiles/76561198037509122#!/compare/1533168000/1533254400

https://backpack.tf/profiles/76561198036394691#!/compare/1533168000/1533254400

Sale 8

Sold for a Terror-Watt Das Gutenkuttehaaren (21 keys)

https://backpack.tf/profiles/76561198036394691#!/compare/1533254400/1533427200

https://backpack.tf/profiles/76561198129860851#!/compare/1533254400/1533340800

Mini for the Das Gutenkuttehaaren

Sold for 19.5 keys = 20 keys

https://backpack.tf/profiles/76561198047322137#!/compare/1533600000/1533686400

https://backpack.tf/profiles/76561198211885115#!/compare/1533600000/1533686400

Sold for 22 keys

https://backpack.tf/profiles/76561198036394691#!/compare/1533427200/1533600000

https://backpack.tf/profiles/76561198047322137#!/compare/1533513600/1533600000

Taking 21 keys.

Sale 9

Untrace

https://backpack.tf/profiles/76561198129860851#!/compare/1533686400/1533772800

https://backpack.tf/profiles/76561198231709968#!/compare/1533686400/1533772800

Sale 10

Sold for a Duped Circling TF Logo Dr.s Dapper Topper (30 keys)

https://backpack.tf/profiles/76561198231709968#!/compare/1533945600/1534032000

https://backpack.tf/profiles/76561198063070081#!/compare/1534032000/1534118400

Mini for the Duped TF Logo Dapper Topper

Sold for 30 keys

https://backpack.tf/profiles/76561198017738651#!/compare/1532304000/1532476800

https://backpack.tf/profiles/76561198063070081#!/compare/1532304000/1532476800

Taking 30 keys.

Sale 11

Bulk

https://backpack.tf/profiles/76561198063070081#!/compare/1535241600/1535328000

https://backpack.tf/profiles/76561198073739851#!/compare/1535155200/1535241600

Sale 12

Sold for 22 keys

https://backpack.tf/profiles/76561198073739851#!/compare/1535241600/1535328000

https://backpack.tf/profiles/76561198337734785#!/compare/1535155200/1535241600

Sale 13

Sold for 23 keys

https://backpack.tf/profiles/76561198337734785#!/compare/1535500800/1535587200

https://backpack.tf/profiles/76561198193704069#!/compare/1535500800/1535587200

Sale 14

https://marketplace.tf/items/701;5;u58

http://manic.tf/keyprice/?at=2018-09-01

Sold for $51.5 / $1.88 = 27.39 keys = 27 keys

Sales: 21 / 22 / 22 / 23 / 24 / 27 / 28 / 30 / 32

Buyers at just above 20 keys. All 3 21 and 22 key sales went to buy orders that existed around that time. (Thanks szyмiв for pointing that out.)

Sellers at 27 keys (fresh), 28 keys (2 weeks old), 30 keys (1 month old) 32 keys (2 months old)

Due to the unsold at 28 we can exclude the 28, 30 and 32 key sales.

23-27 it is then.