Cutting some sales off.

https://backpack.tf/item/7109126985

Sale 1) ?

https://backpack.tf/profiles/76561198118873486#!/compare/1535846400/1535932800

https://backpack.tf/profiles/76561198030549127#!/compare/1536019200/1538179200

https://backpack.tf/item/3490727356

Sale 2) ?

https://backpack.tf/profiles/76561198054678875#!/compare/1535673600/1535846400

Sale 3) Sold for 38 Keys?

https://backpack.tf/profiles/76561198002757046#!/compare/1536364800/1536451200

https://backpack.tf/profiles/76561198023860651#!/compare/1536364800/1536451200

https://backpack.tf/item/3638255853

Sale 4) Sold for a Vivid Plasma Toadstool Topper

https://backpack.tf/profiles/76561198056793444#!/compare/1537056000/1537142400

This sale was used to price that.

https://backpack.tf/item/4537734876

Sale 5) Sold for some number of Keys

https://backpack.tf/profiles/76561198098536989#!/compare/1535587200/1535673600

https://backpack.tf/profiles/76561198299093168#!/compare/1535587200/1535673600 - Here's where some Keys went

Sale 6) Sold for a Purple Energy Birdcage (28 Keys) + Dead Presidents Das Hazmattenhatten (18.5 Keys) + ~2 Keys of Items

https://backpack.tf/profiles/76561198797842085#!/compare/1538265600/1538352000

https://backpack.tf/profiles/76561198094422677#!/compare/1538352000/1538438400

28 + 18.5 + 2 = 48.5, which rounds to 49 Keys

Dead Presidents Das Hazmattenhatten Mini

https://backpack.tf/suggestion/5bf7c3b444325a6ec5225009 - Using the sales at 16 Keys, 18 Keys, and the Translator (16.5 Keys) + 4 Keys

Taking 16 - 21 Keys

Atomic Universal Translator Micro

https://marketplace.tf/items/30658;5;u92 - Sales ranging from 17 Keys to 20 Keys

https://imgur.com/a/emhtkiv - Unsolds at 16 Keys (19 Days, 6 Days, and 4 Hours) and 18 Keys (12 Days and 13 Days); highest Buyer is 15 Keys

https://backpack.tf/item/6682742770 - 16 Keys, 19 Days

https://backpack.tf/item/4263389856 - 16 Keys, 6 Days

https://backpack.tf/item/7188939070 - 16 Keys, 4 Hours

https://backpack.tf/item/6515504344 - 18 Keys, 12 Days

https://backpack.tf/item/7245797332 - 18 Keys, 13 Days

https://backpack.tf/u/76561198380701023 - Buyer

Taking 16 - 17 Keys

https://backpack.tf/item/5012559103

Sale 7) Bulk sale for a Nebula Captain Space Mann

https://backpack.tf/profiles/76561198067581903#!/compare/1536796800/1536883200

Sale 8) Sold for 38 Keys

https://backpack.tf/profiles/76561198202477376#!/compare/1540944000/1541376000

Sale 9) Sold for a Sunbeams Bomb Beanie + 1 Key + ~1 Key of Items

https://backpack.tf/profiles/76561198200222062#!/compare/1541289600/1541376000

https://backpack.tf/profiles/76561198168148171#!/compare/1541289600/1541376000

Since the Beanie now has a Seller at 35 Keys, I'll count this sale as low ---> https://imgur.com/a/IYcwJBq

Sale 10) Sold for a Stormy Storm Tipped Lid (42 Keys) + ~3 Keys of Items

https://backpack.tf/profiles/76561198168148171#!/compare/1541376000/1541462400

https://backpack.tf/profiles/76561198039731024#!/compare/1541376000/1541462400

42 + 3 = 45 Keys

https://marketplace.tf/items/30425;5;u58 - Sold for $100 when Keys were ~$1.81 each and $119.99 when Keys were $1.72 each

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

100 / 1.81 = 55.25, which rounds to 55 Keys

119.99 / 1.72 = 69.76, which was capped by the Buyout of 60 Keys as mentioned here: https://backpack.tf/suggestion/5bf8d1e944325a23e17131f5