Hot and Steamy

https://backpack.tf/item/6838871359

Sale 1) Sold for 19 Keys + ~1 Key of Items

https://backpack.tf/profiles/76561198202085200#!/compare/1539216000/1540425600

19 + 1 = 20 Keys

Sale 2) Sold + ~8 Keys of Items for 35 Keys

https://backpack.tf/profiles/76561198352969437#!/compare/1540166400/1540339200

High outlier.

Sale 3) ?

https://backpack.tf/profiles/76561198430767896#!/compare/1540339200/1540512000

https://backpack.tf/item/7255132723

Sale 4) ?

https://backpack.tf/profiles/76561198183297649#!/compare/1542153600/1542585600

Sale 5) Sold for 17 Keys + 7 Refined

https://backpack.tf/profiles/76561198028021876#!/compare/1542585600/1542758400

Low outlier.

https://backpack.tf/item/1118061334

Sale 6) Sold for a Stormy Storm Reggaelator (14 Keys) + ~3 Keys of Items

https://backpack.tf/profiles/76561198051888880#!/compare/1539388800/1539475200

Low outlier.

Reggae Mini

https://imgur.com/a/VuNw82I - 2 Week Seller at 14 Keys

https://backpack.tf/item/1716048333

https://marketplace.tf/items/390;5;u29 - Sold for $34.17 (~20 Keys)

Taking 14 Keys.

Sale 7) Sold + ~3 Keys of Items for a Purple Confetti Towering Pillar of Hats

https://backpack.tf/profiles/76561198051888880#!/compare/1539561600/1539648000

Not a good sale to use for either.

Sale 8) Quicksold for 17 Keys

https://backpack.tf/profiles/76561198002391950#!/compare/1539561600/1539648000

Sale 9) ?

https://backpack.tf/profiles/76561198266876790#!/compare/1539734400/1539820800

https://backpack.tf/profiles/76561198037248506#!/compare/1539734400/1539820800

Sale 10) ?

https://backpack.tf/profiles/76561198037248506#!/compare/1539993600/1540080000

Sale 11) ?

https://backpack.tf/profiles/76561198863934498#!/compare/1545264000/1545350400

New Sales - Credits to Polar

https://backpack.tf/profiles/76561198301097706#!/compare/1548374400/1548460800 - Sold + 1 Key for a Blizzardy Storm Company Mann

https://backpack.tf/profiles/76561198301097706#!/compare/1548201600/1548374400 - Sold for a Green Confetti Glengarry Bonnet (16.5 Keys) + 6 Keys

Rounds to 23 Keys

Bonnet Mini

https://backpack.tf/profiles/76561198374540031#!/compare/1545177600/1545350400 - Sold for an Orbiting Fire Ye Olde Baker Boy (16.5 Keys)

https://marketplace.tf/items/611;5;u36 - Sold for $49.99 when Keys were ~$1.72 each and $43 when Keys were $1.75 each

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

49.99 / 1.72 = 29.06, which rounds to 29 Keys

43 / 1.75 = 24.57, which rounds to 25 Keys, but this is capped by the Buyout of 23 Keys as mentioned below

https://backpack.tf/suggestion/5c51c17144325a2e760c9623#comment-5c51c752cf6c75549d50e8b9

Calling 27 and 29 high because of all of the lower sales.