State your case.

https://backpack.tf/item/6280137032

Sale 1) Bulk

https://backpack.tf/profiles/76561198303326725#!/compare/1521936000/1522195200

Sale 2) Bulk

https://backpack.tf/profiles/76561198109838613#!/compare/1522195200/1522281600

Sale 3) Sold for a Circling Heart Modest Metal Pile of Scrap (62 Keys)

https://backpack.tf/profiles/76561198021272428#!/compare/1525564800/1525651200

Modest Mini

https://backpack.tf/item/5108116232

Sale 1) Sold for a Tesla Coil Vive la France (70 Keys)

https://backpack.tf/profiles/76561198022776135#!/compare/1522368000/1522540800

Vive Micro

https://backpack.tf/profiles/76561198102186957#!/compare/1522972800/1523059200 - Sold + ~3 Keys of Items for a Tesla Rifleman + ~3.3 Keys of Items

https://backpack.tf/profiles/76561198346664888#!/compare/1522972800/1523059200 - Sold for a Tesla Coil Brotherhood of Arms

https://backpack.tf/profiles/76561198127657749#!/compare/1527724800/1528070400 - Sold + ~1 Key of Items for a Tesla Coil Salty Dog

https://backpack.tf/profiles/76561198346664888#!/compare/1528934400/1529020800 - Sold + 10 Keys + ~7 Keys of Items for a Vivid Plasma Cotton Head

https://backpack.tf/profiles/76561198275056487#!/compare/1521849600/1521936000 - Sold for a Pro KS Aussie Scatter (~39 Keys) + ~6 Keys of Items

https://backpack.tf/profiles/76561198326093863#!/compare/1523404800/1523491200 - Sold for a Power Surge Soldered + Searing Grimm + 2 Keys

https://marketplace.tf/items/30422;5;u108 - Sold for $149.99 when Keys were ~$1.97 each (149.99 / 1.97 = 76 Keys)

https://imgur.com/a/7V6l2gk - Seller at 64 Keys

Taking 64 - 76 Keys, as the other sales fall within or on the edges of this range.

Sale 2) Sold for a Starstorm Insomnia Texas Slim's Dome Shine (50 Keys) + 4 Keys

https://backpack.tf/profiles/76561198112516663#!/compare/1525219200/1525305600

50 + 4 = 54 Keys

Dome Micro

https://backpack.tf/profiles/76561198113853563#!/compare/1522972800/1523059200 - Sold for a Miami Executioner + DP Pillar (~55 Keys together)

https://backpack.tf/profiles/76561198048851745#!/compare/1527897600/1527984000 - Sold for 43 Keys + ~2 Keys of Items

https://backpack.tf/profiles/76561198253606754#!/compare/1528243200/1528329600 - Sold for a Smoking Brotherhood of Arms (50 Keys)

Brotherhood Nano

https://backpack.tf/profiles/76561198196792419#!/compare/1528243200/1528329600 - Sold + ~26 Keys of stuff for a Blizzardy TC + ~13 Keys of Items

https://backpack.tf/profiles/76561198173678813#!/compare/1528243200/1528329600 - Quicksold for 38 Keys

https://backpack.tf/profiles/76561198031126990#!/compare/1529193600/1529366400 - Sold for 40 Keys

https://backpack.tf/profiles/76561198049149130#!/compare/1525737600/1525996800 - Sold for a D@D Hottie's (44 Keys) + Orb. Fire Desert (~60 Keys total)

https://backpack.tf/profiles/76561198067781788#!/compare/1527292800/1527379200 - Sold + 16 Keys + ~3 Keys of Items for a Neutron KE

http://www.tf2outpost.com/trade/29665349 - Capped by the Buyout of 50 Keys

https://backpack.tf/profiles/76561198081445646#!/compare/1528934400/1529020800 - Sold for 42 Keys

Taking 40 - 60

Sale 3) Sold + 2 Keys + ~1 Key of Items for a Sulphurous Swagman's Swatter (38 Keys) + Searing Plasma Defiant Spartan (21.5 Keys)

https://backpack.tf/profiles/76561198310127340#!/compare/1525219200/1525305600

https://backpack.tf/profiles/76561198161625387#!/compare/1525219200/1525305600

38 + 21.5 - 2 - 1 = 56.5, which rounds to 57 Keys

Swatter Micro

https://backpack.tf/suggestion/5b26a5ae44325a2856724d40 - 38 Keys

Spartan Micro

https://backpack.tf/suggestion/5b27d30c44325a07d7537339 - 21.5 Keys

Sale 4) Sold for a Duped Purple Energy Towering Pillar of Hats + ~1 Key of Items

https://backpack.tf/profiles/76561198232041512#!/compare/1525564800/1525651200

Fits in the range.

Duped PE Pillar Micro

https://backpack.tf/profiles/76561198232041512#!/compare/1525910400/1525996800 - Sold for a Scorching Ketche + ~26 Keys of Taunts + ~4 Keys of Items