Suggestion Version 3.0 w/ fixed price range + information... again.

https://backpack.tf/classifieds?item=Smoking%20Jacket&quality=11&tradable=1&craftable=1&australium=-1&killstreak_tier=0

Buy Orders start at 4.21, ~4.2 keys.

Sell Orders start at 10 keys.

Bot.tf Sales:

https://ibb.co/YLZ1KkY

2 Sold for 5 keys.

Marketplace.tf Sales:

https://ibb.co/KjnqMzm

1 Sold for $13.72/ 1.89 = 7.25 keys.

1 Sold for $15.47/ 1.85 = 8.36, ~8.35 keys.

1 Sold for $15.63/ 1.87 = 8.35 keys.

1 Sold for $9.43/ 1.88 = 5.01, ~5 keys.

1 Sold for $9.00/ 1.87 = 4.81, ~4.8 keys.

1 Sold for $15.15/ 1.84 = 8.23, ~8.25 keys.

1 Sold for $8.65/ 1.87 = 4.62, ~4.6 keys.

1 Sold for $9.89/ 1.85 = 5.34, ~5.35 keys.

1 Sold for $10.30/ 1.83 = 5.62, ~5.6 keys.

1 Sold for $10.99/ 1.84 = 5.97, ~5.95 keys.

SCM Sales:

https://ibb.co/xzdRsTD

1 Sold for $11.26/ 2.30 = 4.89, ~4.9 keys.

1 Sold for $10.50/ 2.23 = 4.7 keys.

1 Sold for $9.15/ 2.23 = 4.1 keys.

1 Sold for $9.52/ 2.33 = 4.09, ~4.1 keys.

1 Sold for $9.97/ 2.35 = 4.22, ~4.2 keys.

Excluding any sales that are above 6 keys, as they appear to be obvious outlier sales compared to the other sales that are around 4.2 - 5.95 keys. Additionally, anything above 6 keys will be high here looking at scm sellers/sales: https://steamcommunity.com/market/listings/440/Strange%20Smoking%20Jacket

Thank you for that additional information, Blaze.

Going with 4.2 - 5.95 keys.