Suggestion: Burning Flames Head of Defense at 32–42 keys

During the times of the sales on marketplace, the past buyers were up to 27-30~. Current buyers are also higher, excluding the 3 sales at 23, 24, and 25, as they are low outliers here.

Current marketplace sellers at the value of about 43~, which show that 47 is a high outlier here.

Going with 35-39 here.

Proof by https://backpack.tf/u/76561198061108999

https://marketplace.tf/items/tf2/31114;5;u13

https://backpack.tf/item/9246766337

https://backpack.tf/item/9233314339

https://backpack.tf/item/9232786367

- new sales at $69.99 (40 keys), $65.99 (37 keys), $77.78 (42 keys)

https://backpack.tf/profiles/76561198047237459#!/compare/1605484800/1605571200

https://backpack.tf/profiles/76561199068665221#!/compare/1605484800/1605571200 - sold for Hot Festivized Professional Killstreak Uranium Air Strike (Well-Worn)

https://backpack.tf/profiles/76561198195420449#!/compare/1605484800/1605571200 - sold with 3~ keys for Aces High Defragmenting Hard Hat 17%

https://backpack.tf/profiles/76561198098357074#!/compare/1603584000/1604102400

https://backpack.tf/profiles/76561198195420449#!/compare/1603843200/1604102400 - sold for 32 keys

https://backpack.tf/profiles/76561198097271466#!/compare/1603152000/1603238400

https://backpack.tf/profiles/76561198098357074#!/compare/1603152000/1603238400 - sold for 32 keys

https://backpack.tf/profiles/76561197971485686#!/compare/1604793600/1604880000

https://backpack.tf/profiles/76561198139111928#!/compare/1604361600/1604880000 - bulk

https://backpack.tf/profiles/76561198022652091#!/compare/1603411200/1603584000

https://backpack.tf/profiles/76561198063640894#!/compare/1603497600/1603584000 - bulk

https://backpack.tf/profiles/76561198021055079#!/compare/1604534400/1604620800

https://backpack.tf/profiles/76561198048841930#!/compare/1604448000/1604620800 - sold for 35 keys

https://backpack.tf/profiles/76561198015378996#!/compare/1604016000/1604188800

https://backpack.tf/profiles/76561198021055079#!/compare/1604016000/1604102400 - unsure

https://backpack.tf/profiles/76561197980002937#!/compare/1602720000/1602979200 - unsure

https://backpack.tf/profiles/76561198026953607#!/compare/1602201600/1602547200

https://backpack.tf/profiles/76561197980002937#!/compare/1602460800/1602547200 - sold for 27 keys

https://backpack.tf/profiles/76561198307602421#!/compare/1604707200/1604793600

https://backpack.tf/profiles/76561198120585187#!/compare/1604534400/1604793600 - sold for 33 keys

sales at 23, 24, 25, 27, 32, 32, 33, 35, 35, 37, 39, 40, 42, 47

maybe 32 - 42 keys could work here since those lower sales seem to have sold pretty quick

Going with 32-42 keys, proof by users shown