New sales:

https://backpack.tf/profiles/76561199389372563#!/compare/1744848000/1744934400 - 24 Keys to a buy order

https://backpack.tf/profiles/76561198066933519#!/compare/1739318400/1740009600 - 30 Keys

https://backpack.tf/profiles/76561198312892271#!/compare/1740700800/1741046400 - Dumped with 4 Keys for a Miami Nights one (27 Keys)

https://backpack.tf/profiles/76561199389372563#!/compare/1741651200/1741824000 - ?

https://backpack.tf/profiles/76561198186261565#!/compare/1739750400/1740009600 - 25 Keys

https://backpack.tf/profiles/76561198000026735#!/compare/1739750400/1739923200 - 29 Keys

https://backpack.tf/profiles/76561198073818313#!/compare/1739664000/1739923200 - 20 Keys to a bot site

https://backpack.tf/profiles/76561199026390261#!/compare/1739923200/1740009600 - ?

https://backpack.tf/profiles/76561198349848918#!/compare/1743379200/1743465600 - ?

https://backpack.tf/profiles/76561198089415757#!/compare/1743984000/1744156800 - ?

https://backpack.tf/profiles/76561198193494809#!/compare/1743724800/1743811200 - 26 Keys to a buy order

https://backpack.tf/profiles/76561198070143161#!/compare/1738195200/1738368000 - 30 Keys

https://backpack.tf/profiles/76561198070143161#!/compare/1738713600/1739404800 - 28 Keys to a buy order

https://backpack.tf/profiles/76561198053514813#!/compare/1737417600/1745712000 - ?

https://backpack.tf/profiles/76561199177197071#!/compare/1744156800/1744329600 - ?

https://backpack.tf/profiles/76561198409186955#!/compare/1741219200/1744329600 - ?

https://backpack.tf/profiles/76561198109872491#!/compare/1743724800/1744329600 - ?

https://backpack.tf/profiles/76561198969065665#!/compare/1744329600/1744416000 - 30 Keys

https://backpack.tf/profiles/76561198012537041#!/compare/1743033600/1744502400 - ?

https://backpack.tf/profiles/76561198207690748#!/compare/1737244800/1738108800 - ?

https://backpack.tf/profiles/76561198138745366#!/compare/1738886400/1739750400 - ?

https://backpack.tf/profiles/76561198878675886#!/compare/1739923200/1741564800 - ?

https://backpack.tf/profiles/76561198858282680#!/compare/1740614400/1740700800 - 32 Keys

https://backpack.tf/profiles/76561198165548985#!/compare/1740960000/1741392000 - ?

https://backpack.tf/profiles/76561198143715421#!/compare/1741132800/1741219200 - ?

https://backpack.tf/profiles/76561199026390261#!/compare/1741392000/1741478400 - 30 Keys

https://backpack.tf/profiles/76561198977562505#!/compare/1741824000/1742342400 - ?

https://backpack.tf/profiles/76561199059698603#!/compare/1743120000/1743206400 - Strange Stormy Storm Law (46 Keys)

https://marketplace.tf/items/tf2/31469;5;u360 - $74.99 x7 (39 to 41 Keys) and a sale at $99.99 (52 Keys, high)

Sales missed when this was made:

https://backpack.tf/profiles/76561198050359148#!/compare/1731369600/1732147200 - ?

https://backpack.tf/profiles/76561198188093413#!/compare/1734825600/1734912000 - ?

https://backpack.tf/profiles/76561199489181102#!/compare/1735516800/1735603200 - ?

https://backpack.tf/profiles/76561199389372563#!/compare/1737676800/1737763200 - ?

https://backpack.tf/profiles/76561198212703000#!/compare/1729900800/1729987200 - 41 Keys

https://backpack.tf/profiles/76561199776827890#!/compare/1729900800/1729987200 - Electricity Gentlemannus (20.5 Keys) + Uber Blaze Gentlemannus (18 Keys)

https://backpack.tf/profiles/76561199026390261#!/compare/1744243200/1744329600 - Orbiting Fire Big Country?

https://backpack.tf/profiles/76561198038963425#!/compare/1740441600/1746576000 - ?

https://backpack.tf/profiles/76561198177872379#!/compare/1734220800/1734307200 - Marketplace

https://backpack.tf/profiles/76561198093234248#!/compare/1733097600/1734307200 - Bulk

https://backpack.tf/profiles/76561198147668532#!/compare/1744848000/1745193600 - ?

https://backpack.tf/profiles/76561199389372563#!/compare/1733875200/1733961600 - 23 Keys to a buy order

https://backpack.tf/profiles/76561199389372563#!/compare/1734998400/1735084800 - ?

https://backpack.tf/profiles/76561198080686432#!/compare/1729036800/1736640000 - ?

https://backpack.tf/profiles/76561199581722058#!/compare/1734739200/1734825600 - ?

https://backpack.tf/profiles/76561199197138174#!/compare/1734048000/1734307200 - ?

https://backpack.tf/profiles/76561198094818081#!/compare/1737763200/1737849600 - 32 Keys

https://backpack.tf/profiles/76561198094818081#!/compare/1731715200/1731801600 - Bulk sale

https://backpack.tf/profiles/76561198062290614#!/compare/1730851200/1731801600 - Bulk sale

https://backpack.tf/profiles/76561198149459336#!/compare/1731196800/1731283200 - 30 Keys

https://backpack.tf/profiles/76561199026390261#!/compare/1734048000/1734134400 - ?

https://backpack.tf/profiles/76561198070181630#!/compare/1734825600/1739664000 - 26 to 28 Keys to a buy order

https://backpack.tf/profiles/76561198014914678#!/compare/1730851200/1731110400 - ?

https://backpack.tf/profiles/76561198371279817#!/compare/1730246400/1730419200 - 25 Keys (20 were used for the Hazard Handler)

https://backpack.tf/profiles/76561199581722058#!/compare/1736035200/1736121600 - ?

https://backpack.tf/profiles/76561198349848918#!/compare/1735430400/1735516800 - ?

https://backpack.tf/profiles/76561199223616865#!/compare/1731110400/1731196800 - ?

https://backpack.tf/profiles/76561198122426122#!/compare/1736294400/1737158400 - ?

https://backpack.tf/profiles/76561198421223960#!/compare/1734480000/1734566400 - ?

https://backpack.tf/profiles/76561198170931642#!/compare/1731542400/1732060800 - ?

https://backpack.tf/profiles/76561198964926617#!/compare/1731369600/1732320000 - ?

https://backpack.tf/profiles/76561199389372563#!/compare/1733529600/1733616000 - ?

https://backpack.tf/profiles/76561198807635613#!/compare/1734048000/1734134400 - 21 Keys + ~2 Keys of Items + ~1 Key of Refined

https://backpack.tf/profiles/76561199581722058#!/compare/1732924800/1733011200 - ?

https://backpack.tf/profiles/76561198196622954#!/compare/1732492800/1732579200 - ?

https://backpack.tf/profiles/76561198302774496#!/compare/1731024000/1731110400 - ?

https://backpack.tf/profiles/76561198274778188#!/compare/1730332800/1731456000 - ?

https://backpack.tf/profiles/76561198139932452#!/compare/1736640000/1742860800 - ?

https://backpack.tf/profiles/76561198055621547#!/compare/1729296000/1729555200 - ?

The 27 key sale in this suggestion was a quicksell. That makes the following sale spread, with 6 sales at or under 28 being buy orders / quicksells.

23, 24, 24, 25, 25, 26, 26, 27, 28, 29, 30, 30, 30, 30, 32, 32, 35, 35, 39, 39-41 (x7), 41, 44 (x3), 45, 46, 52

If we focus on only the most recent sales that happened after this suggestion was made, the spread is:

24 (buy order), 25, 26 (buy order), 28 (buy order), 29, 30, 30, 30, 32, 39-41 (x7), 46, 52

Buyers in the Classifieds are 25, and STN pays 26. A range of 29 - 41 would work to trim the spread slightly and give precedence to the newer sales.