Starkiller

https://backpack.tf/item/5201428007

Sale 1) ?

https://backpack.tf/profiles/76561198057894608#!/compare/1555891200/1556928000

https://backpack.tf/item/5186061280

Sale 2) Sold + Australium Force-a-Nature for a Strange Starstorm Insomnia Killer Exclusive

https://backpack.tf/profiles/76561198804015732#!/compare/1550534400/1550620800

https://backpack.tf/profiles/76561198066870980#!/compare/1547769600/1550620800

This priced the Strange version.

https://backpack.tf/item/5245274516

Sale 3) Sold for a Circling Heart Patriot Peak (67.5 Keys)

https://backpack.tf/profiles/76561198089689746#!/compare/1553817600/1553904000

https://backpack.tf/profiles/76561198113488534#!/compare/1553558400/1553904000

https://imgur.com/a/MskiSfZ - Had a Buyout of 74 Keys.

Rounds to 68 Keys

Peak Mini

https://backpack.tf/suggestion/5cd61c89678072020e698e17 - 67.5 Keys

Sale 4) Sold for a Sulphurous Frenchman's Beret (38 Keys) + 18 Keys + Negligible Items

https://backpack.tf/profiles/76561198113488534#!/compare/1553990400/1554076800

https://backpack.tf/profiles/76561198046102461#!/compare/1553990400/1554076800

Low outlier.

Sale 5) Sold for 47 Keys + Black Max's Head (~22 Keys)

https://backpack.tf/profiles/76561198046102461#!/compare/1553990400/1554076800

https://backpack.tf/profiles/76561198080594357#!/compare/1553990400/1554076800

47 + 22 = 69 Keys

Sale 6) Sold for Stormy 13th Hour Counterfeit Billycock + 9 Keys

https://backpack.tf/profiles/76561198080594357#!/compare/1554163200/1554249600

Using this for the Counterfeit.

Sale 7) Sold for a Galactic Gateway Hephaistos' Handcraft

https://backpack.tf/profiles/76561198218497692#!/compare/1554163200/1554249600

Using this for the Handcraft.

Sale 8) Sold for a Terror-Watt Crone's Dome (74 Keys)

https://backpack.tf/profiles/76561198112516663#!/compare/1554854400/1555027200

Sale 9) Sold for a Circling Heart Human Cannonball + 3 Keys

https://backpack.tf/profiles/76561198796559482#!/compare/1555113600/1555200000

https://backpack.tf/profiles/76561198342161127#!/compare/1555113600/1555200000

Low outlier.

https://backpack.tf/item/5185841370

Sale 10) Sold + 15 Keys for a Searing Plasma Law

https://backpack.tf/profiles/76561198161653465#!/compare/1556755200/1556841600

https://backpack.tf/profiles/76561198374081436#!/compare/1556755200/1556841600

The 15 Keys don't appear because they immediately sold in sale 11. The Law has no Mini, so this sale can update that.

Sale 11) Sold + 15 Keys for a Scorching Flames Universal Translator (81 Keys)

https://backpack.tf/profiles/76561198374081436#!/compare/1556755200/1556841600

https://backpack.tf/profiles/76561198306872661#!/compare/1556755200/1556841600

81 - 15 = 66 Keys

Translator Mini

https://backpack.tf/suggestion/5ccdcdd5d3817270dd5c5099 - 81 Keys

https://backpack.tf/item/5265344989

Sale 12) Bulk sale for a Burning Executioner

https://backpack.tf/profiles/76561198081270783#!/compare/1551398400/1551571200

Sale 13) Bulk sale for a Frostbite Modest

https://backpack.tf/profiles/76561198189381361#!/compare/1551484800/1551571200

Sale 14) Sold + Frostbite Combustible Kabuto (54 Keys) + 15 Keys for a Poisoned Shadows Towering Pillar of Hats

https://backpack.tf/profiles/76561198171496838#!/compare/1551744000/1551830400

https://backpack.tf/profiles/76561198258264645#!/compare/1551744000/1551830400

This would better be used for the Pillar.

https://marketplace.tf/items/538;5;u109 - Sold for $136.62 when Keys were ~$1.79 each

https://marketplace.tf/items/5021;6/Mann%20Co.%20Supply%20Crate%20Key

136.62 / 1.79 = 76.32, which rounds to 76 Keys