Sold for 37 Pure

https://backpacktf.trade/profiles/76561198081851169#!/compare/1640995200/1641081600

Sold for 40 Pure

https://backpacktf.trade/profiles/76561198237679984#!/compare/1644710400/1644883200

Sold for 35 Pure - Outlier

https://backpack.tf/profiles/76561198202592232#!/compare/1642118400/1642377600

Sold for 37 Pure

https://backpack.tf/profiles/76561199203355184#!/compare/1640995200/1641081600

Sold for 44 Pure

https://backpack.tf/profiles/76561198097271466#!/compare/1644451200/1644537600

Sold w/ 8 Keys for a Burning Snack Stack, but I can't find a mini on the Stack, it would likely be around ~50 Keys, so outlier either way.

https://backpack.tf/profiles/76561198382824443#!/compare/1643673600/1643760000

Extra sales provided by Squeezy Lemon

New sales:

https://backpack.tf/profiles/76561198256840282#!/compare/1646179200/1646265600

https://backpack.tf/profiles/76561198220720512#!/compare/1646179200/1646265600 - Sold with 7 keys for a Burning Flames Steel Shako - Can be used there

Buyout was 50 keys https://gladiator.tf/listings/621f55929d40103053fa3d6d

https://backpack.tf/profiles/76561198987926475#!/compare/1646092800/1646179200

https://backpack.tf/profiles/76561198256840282#!/compare/1646092800/1646179200 - 53 keys removed but I doubt it was 53 since they listed for 50 afterwards. I'd be cautious and just exclude this.

Missing sales:

https://backpack.tf/profiles/76561198040186479#!/compare/1643241600/1643328000 - Blizz Bandana, looks low

https://backpack.tf/profiles/76561198037171335#!/compare/1642982400/1643155200 - Bulk

https://backpack.tf/profiles/76561198054796945#!/compare/1640390400/1640563200

https://backpack.tf/profiles/76561198109986831#!/compare/1640476800/1640563200 - Sold for 31 keys

https://backpack.tf/profiles/76561198044254513#!/compare/1639785600/1639872000 - Sold for 30 keys

https://backpack.tf/profiles/76561198850274253#!/compare/1640736000/1640822400

https://backpack.tf/profiles/76561198390448212#!/compare/1640736000/1640822400 - Sold for 33 keys

https://backpack.tf/profiles/76561199185696636#!/compare/1640390400/1640476800

https://backpack.tf/profiles/76561198850274253#!/compare/1640390400/1640476800 - Untrace

https://backpack.tf/profiles/76561199185696636#!/compare/1638662400/1639699200

https://backpack.tf/profiles/76561197971403645#!/compare/1639612800/1639699200 - Looks like 35 but they don't match

https://backpack.tf/profiles/76561198049526097#!/compare/1643846400/1643932800

https://backpack.tf/profiles/76561198160772050#!/compare/1643846400/1643932800 - Sold for 42 keys

https://backpack.tf/profiles/76561198049526097#!/compare/1643068800/1643846400

https://backpack.tf/profiles/76561198054272235#!/compare/1643760000/1643846400 - Bulk

https://backpack.tf/profiles/76561199199711319#!/compare/1641945600/1642118400

https://backpack.tf/profiles/76561198054272235#!/compare/1641945600/1642032000 - High

https://backpack.tf/item/10897217098 https://marketplace.tf/items/tf2/30767;5;u200

$120 / $1.84 = 65 keys

https://marketplace.tf/items/tf2/30767;5;u200

$119.99 / $1.83 = 66 keys

There used to be buyers at 37 but they are now gone, but all of the most recent sales suggest that anything below that would be low either way, so this seems like a fair range.