Do you even lift, bro?

https://backpack.tf/item/6294385366

Sale 1) Bulk sale for an Aces High Das Ubersternmann

https://backpack.tf/profiles/76561198279609240#!/compare/1559606400/1559952000

https://backpack.tf/item/6256427268

Sale 2) SCM sale

https://backpack.tf/profiles/76561198269104470#!/compare/1557532800/1557705600

https://backpack.tf/profiles/76561198113899098#!/compare/1558310400/1558396800

Sale 3) SCM sale

https://backpack.tf/profiles/76561198113899098#!/compare/1558396800/1558483200

https://backpack.tf/item/6256448933

Sale 4) SCM sale

https://backpack.tf/profiles/76561198806737446#!/compare/1558915200/1559001600

https://backpack.tf/profiles/76561197984688600#!/compare/1559520000/1560211200

https://backpack.tf/item/6348402340

Sale 5) ?

https://backpack.tf/profiles/76561198105098440#!/compare/1562544000/1562716800

https://backpack.tf/profiles/76561198950294215#!/compare/1562630400/1562716800

Sale 6) Quicksold for 5 Keys

https://backpack.tf/profiles/76561198082294224#!/compare/1562716800/1562803200

Sale 7) Bulk sale for a Bubbling Villain's Veil

https://backpack.tf/profiles/76561198002757046#!/compare/1562803200/1562889600

https://backpack.tf/profiles/76561198798324694#!/compare/1562803200/1562889600

https://backpack.tf/item/6485299691

Sale 8) ?

https://backpack.tf/profiles/76561198386366689#!/compare/1559001600/1561852800

Sale 9) Sold for 6 Keys

https://backpack.tf/profiles/76561198165205268#!/compare/1561161600/1561248000

Sale 10) ?

https://backpack.tf/profiles/76561198152897007#!/compare/1561248000/1561334400

https://backpack.tf/profiles/76561198118624520#!/compare/1561248000/1561334400

https://backpack.tf/item/6794055837

Sale 11) Sold for 6 Keys

https://backpack.tf/profiles/76561198340634356#!/compare/1558310400/1558396800

https://backpack.tf/profiles/76561198096382522#!/compare/1558396800/1558656000

Sale 12) Bulk sale for a Cloud 9 Modest Pile of Hat

https://backpack.tf/profiles/76561198096382522#!/compare/1558828800/1558915200

https://backpack.tf/profiles/76561198257905663#!/compare/1558742400/1558828800

Sale 13) Bulk sale for a Smoking Brotherhood of Arms

https://backpack.tf/profiles/76561198257905663#!/compare/1561075200/1561248000

Sale 14) Quicksold for 5 Keys

https://backpack.tf/profiles/76561198100587328#!/compare/1561161600/1561248000

https://backpack.tf/item/6821694867

Sale 15) Bulk sale with other Unusual Taunts for Keys and Refined

https://backpack.tf/profiles/76561198001229964#!/compare/1559692800/1559779200

https://backpack.tf/profiles/76561198202186637#!/compare/1559692800/1559779200

https://backpack.tf/item/7020892010

Sale 16) ?

https://backpack.tf/profiles/76561198143470931#!/compare/1560124800/1560643200

https://backpack.tf/profiles/76561198954097331#!/compare/1561680000/1561852800

https://backpack.tf/item/7084345732

Sale 17) Sold for 9 Keys

https://backpack.tf/profiles/76561198086948995#!/compare/1559088000/1559174400

https://backpack.tf/profiles/76561198059071754#!/compare/1559088000/1559433600

https://backpack.tf/item/7127318957

Sale 18) Sold for ~10 Keys of Items

https://backpack.tf/profiles/76561198325974441#!/compare/1561852800/1561939200

https://imgur.com/a/swOPC9p - Capped by the Buyout of 8 Keys

Sale 19) Sold + 4 Keys for a Miami Nights Pyro's Boron Beanie

https://backpack.tf/profiles/76561198825943127#!/compare/1561939200/1562025600

https://backpack.tf/profiles/76561198033976810#!/compare/1561939200/1562025600

https://backpack.tf/item/7331397970

Sale 20) ?

https://backpack.tf/profiles/76561198003926663#!/compare/1562198400/1562284800

https://backpack.tf/profiles/76561198369477018#!/compare/1562284800/1562371200

3 Keys match here.

Sale 21) ?

https://backpack.tf/profiles/76561198369477018#!/compare/1562630400/1562889600

https://backpack.tf/item/7431507987

Sale 22) ?

https://backpack.tf/profiles/76561198012659809#!/compare/1560470400/1560556800

https://backpack.tf/profiles/76561198128813654#!/compare/1560556800/1560902400

Sale 23) ?

https://backpack.tf/profiles/76561198128813654#!/compare/1562112000/1562198400

https://backpack.tf/item/6252771740

Sale 24) Sold for 7 Keys

https://backpack.tf/profiles/76561198335791307#!/compare/1558828800/1558915200

Sale 25) ?

https://backpack.tf/profiles/76561198413125750#!/compare/1558915200/1559001600

Sale 26) ?

https://backpack.tf/profiles/76561198340634356#!/compare/1559001600/1559088000

https://backpack.tf/profiles/76561198313393318#!/compare/1559001600/1559088000

Sale 27) Bulk sale for a Duped Harvest Moon Jumper's Jeepcap

https://backpack.tf/profiles/76561198313393318#!/compare/1559088000/1559174400

https://backpack.tf/profiles/76561198047941585#!/compare/1559088000/1559174400

https://marketplace.tf/items/tf2/30844;5;u3005 - Sold for $12.59, $12.99, $9.08 (low), $12.99, $9.11 (low), and $12.99

https://marketplace.tf/items/tf2/5021;6 - Keys were $1.81, $1.81, $1.84, and $1.83 each for the non-low sales.

12.59 / 1.81 = 6.95, which rounds to 7 Keys

12.99 / 1.81 = 7.17, which rounds to 7 Keys

12.99 / 1.84 = 7.06, which rounds to 7 Keys

12.99 / 1.83 = 7.10, which rounds to 7 Keys

Given 8 Keys was entirely in items and a buyout cap, I'm excluding 8. Also excluding 9 for being too high and 5 for being too low.

https://imgur.com/a/yAd9Wlf - 5 Hour Seller at 7 Keys, 3 Day Buyer at 5.11 Keys, and a 3 Day Buyer at 5.01 Keys

https://backpack.tf/item/7331397970

https://backpack.tf/u/76561198097271466

https://backpack.tf/u/76561198401509004