First suggestion (second try, range on previous one was wrong), probably a terrible one but I'll try anyway.

Sale 1: Sold with a Strange Prof KS Huntsman for a Miami Nights Nuke (40) + 5 keys? (https://backpack.tf/profiles/76561197999751332#!/compare/1526428800/1526515200)

Sale 2: Sold for 30 pure, might have been a quicksale (https://backpack.tf/profiles/76561198167641486#!/compare/1526774400/1526860800)

Sale 3: Sold for a Miami Nights Executioner + 8 keys and around 1 key in sweets (https://backpack.tf/profiles/76561198353195301#!/compare/1527292800/1527465600)

Sale 4: Sold with a Spec KS Aussie Grenade Launcher for a Haunted Ghosts Salty Dog (https://backpack.tf/profiles/76561198206760573#!/compare/1527379200/1527552000)

Sale 5: Sold for $95 on marketplace.tf (https://marketplace.tf/items/30976;5;u61) I don't know how to view the median price of keys from that day, if someone posts a comment showing the median key prices for that day I'll close this suggestion and open a new one but we'll say that keys were selling for $1.95 each for the purposes of this suggestion.

Strange Prof KS Huntmans have active buyers for around 6 keys and sellers at 8 keys so we'll value it at around 7 keys

https://backpack.tf/classifieds?item=Huntsman&quality=11&tradable=1&craftable=1&australium=-1&killstreak_tier=3

Spec KS Aussie Grenade Launchers have buyers at around 13.5 keys and sellers for 14 keys so we'll value it at around 14 keys

https://backpack.tf/classifieds?item=Grenade%20Launcher&quality=11&tradable=1&craftable=1&australium=1&killstreak_tier=2

The Nuke has been priced within the last 3 months so it should be elligible as proof, the Salty Dog has an active suggestion at 64 - 75 keys so we'll value it at 68 keys.

https://backpack.tf/suggestion/5ae54faccf6c757fc87fccc7

Mini for Executioner

Sold for an Abduction Universal Translator

https://backpack.tf/profiles/76561198223239048#!/compare/1526256000/1526947200

https://backpack.tf/profiles/76561198081793950#!/compare/1526774400/1526860800

Sold for 26 keys + 1 key in sweets (quicksale)

https://backpack.tf/profiles/76561198143969056#!/compare/1524096000/1524182400

Going to value the Executioner at 33 keys.

Summary

Sale 1: 45 - 7 = 38 keys

Sale 2: 30 keys

Sale 3: 33 + 9 = 42 keys

Sale 4: 68 - 14 = 54 keys, a bit high

Sale 5: 95 / 1.95 = 48 keys

Going with 38 - 48 keys, comments are very welcome since I probably screwed up somewhere.