Sales 1 & 2:

Sold for $79.90 and $55.99 on marketplace.tf

https://marketplace.tf/items/30647;5;u91

https://backpack.tf/item/4219968799 - No B/O

Couldn’t find the other history.

http://manic.tf/keyprice/?at=2018-08-08 - $55.99 / $1.89 = 29.62 keys

http://manic.tf/keyprice/?at=2018-08-21 - $79.9 / $1.9 = 42.05 keys

X = 42

X = 30

Sale 3:

Sold for 38 keys

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1528934400/1529020800

Buyer: https://backpack.tf/profiles/76561198135151187#!/compare/1529020800/1529107200

https://backpack.tf/item/4290522086

X = 38

Sale 4:

Sold for Green Energy Katyusha (Suggestion at 19.5) + Screaming Tiger Runner’s Rhythm (Mini at 17 below)

No outpost

Seller: https://backpack.tf/profiles/76561198114764948#!/compare/1535760000/1535932800

Buyer: https://backpack.tf/profiles/76561198121171912#!/compare/1535587200/1535932800

https://backpack.tf/item/6999123621

X = 37

Sale 5:

Sold for 32 keys + ~1.5 keys in metal/items

Seller: https://backpack.tf/profiles/76561198121171912#!/compare/1535587200/1535932800

Buyer: https://backpack.tf/profiles/76561198047216997#!/compare/1535587200/1536364800

https://backpack.tf/item/6999123621

X = 34

Sale 6:

Sold for 33 keys

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1535673600/1535760000

Buyer: https://backpack.tf/profiles/76561198102362159#!/compare/1535155200/1535760000

https://backpack.tf/item/4883446503

https://i.imgur.com/yXVET9G.png

Only 18 keys appear (on the buyer’s end), but the Baker Boy would’ve sold for keys, then the keys it sold for would’ve been used on the phononaut.

X = 33

Sale 7:

Sold for Abduction Universal Translator (30.5) + Lime Paint (~2)

http://www.tf2outpost.com/trade/29707838 - B/O of 38

Seller: https://backpack.tf/profiles/76561198289219099#!/compare/1531872000/1532736000

Buyer: https://backpack.tf/profiles/76561198081719047#!/compare/1532649600/1532736000

X = 33

Sale 8:

Sold for 33 keys

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1531958400/1532044800

Buyer: https://backpack.tf/profiles/76561198209389815#!/compare/1531958400/1532044800

https://backpack.tf/profiles/76561197996306396#!/compare/1531958400/1532044800 - rest of the keys appear here.

https://backpack.tf/item/6864775845

https://i.imgur.com/yXVET9G.png

X = 33

Sale 9:

Sold for 33 keys

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1534636800/1534723200

Buyer: https://backpack.tf/profiles/76561198214461775#!/compare/1534636800/1534723200

https://backpack.tf/item/6864775845

https://i.imgur.com/yXVET9G.png

X = 33

Sale 10:

Sold for 30 keys + 1 ref

Seller: https://backpack.tf/profiles/76561198132886814#!/compare/1536451200/1536537600

Buyer: https://backpack.tf/profiles/76561198060113354#!/compare/1536451200/1536537600

https://backpack.tf/item/4604509935

X = 30

Sale 11:

Sold for 30 keys

Seller: https://backpack.tf/profiles/76561198171325534#!/compare/1534982400/1535155200

Buyer: https://backpack.tf/profiles/76561198047216997#!/compare/1535155200/1535587200

https://backpack.tf/item/4198679034

X = 30

Sale 12:

Sold for Green Confetti Prince Tavish’s Crown (~13.5) + ~15.5 keys in pure/items

No outpost

Seller: https://backpack.tf/profiles/76561198081129776#!/compare/1530144000/1530230400

Buyer: https://backpack.tf/profiles/76561198076683412#!/compare/1529884800/1530316800

https://backpack.tf/item/4753603894

X = 29

Sale 13:

Sold for 29 keys

Seller: https://backpack.tf/profiles/76561198042555517#!/compare/1529971200/1533254400

Buyer: https://backpack.tf/profiles/76561198081129776#!/compare/1529884800/1529971200

https://backpack.tf/item/4753603894

Keys were spent on bananas and cats.

X = 29

Sale 14:

Sold for 29 keys

Seller: https://backpack.tf/profiles/76561198176297517#!/compare/1536451200/1536537600

Buyer: https://backpack.tf/profiles/76561198309237889#!/compare/1536537600/1536624000

https://backpack.tf/item/6864775845

X = 29

Sale 15:

Sold for 29 keys

Seller: https://backpack.tf/profiles/76561198303813920#!/compare/1529971200/1530057600

Buyer: https://backpack.tf/profiles/76561198089033149#!/compare/1529971200/1530057600

https://backpack.tf/item/4219968799

X = 29

Sale 16:

Sold to a bot for 27 keys + 20 ref

Seller: https://backpack.tf/profiles/76561198330635661#!/compare/1534550400/1534723200

Buyer: https://backpack.tf/profiles/76561198305676157#!/compare/1534636800/1534723200

https://backpack.tf/item/4883446503

https://i.imgur.com/yXVET9G.png

X = 28

Sale 17:

Sold to a bot for 27 keys + 20 ref?

Seller: https://backpack.tf/profiles/76561198062670918#!/compare/1529366400/1533686400

Buyer: https://backpack.tf/profiles/76561198305676157#!/compare/1529798400/1529884800

https://backpack.tf/item/6864775845

https://i.imgur.com/yXVET9G.png

No keys appear, but the exact amount of metal does. That in mind, I doubt bot.tf is incorrect here.

X = 28

Sale 18:

Sold for 27 keys

Seller: https://backpack.tf/profiles/76561198139831684#!/compare/1532736000/1532822400

Buyer: https://backpack.tf/profiles/76561198114001918#!/compare/1532822400/1533081600

https://backpack.tf/item/4226672199

X = 27

Sale 19:

Sold for 27 keys

Seller: https://backpack.tf/profiles/76561198080179568#!/compare/1534464000/1534550400

Buyer: https://backpack.tf/profiles/76561198171325534#!/compare/1534464000/1534550400

https://backpack.tf/item/4198679034

X = 27

Sale 20:

Sold for 27 keys

Seller: https://backpack.tf/profiles/76561198337734785#!/compare/1534377600/1534464000

Buyer: https://backpack.tf/profiles/76561198440055051#!/compare/1533772800/1534464000

https://backpack.tf/item/4226672199

X = 27

Sale 21:

Sold to a bot for 25 keys?

Seller: https://backpack.tf/profiles/76561197982576399#!/compare/1532044800/1532217600

Buyer: https://backpack.tf/profiles/76561198312583107#!/compare/1532131200/1532217600

https://backpack.tf/item/6999123621

https://i.imgur.com/yXVET9G.png

24 keys appear, the 25th was probably spent on tickets or something.

X = 25

Sale 22:

Sold for Spec. KS Aus Sniper Rifle (~22)

Seller: https://backpack.tf/profiles/76561198214461775#!/compare/1534982400/1535068800

Buyer: https://backpack.tf/profiles/76561198418306144#!/compare/1534118400/1534982400

https://backpack.tf/item/6864775845

X = 22

Green Energy Katyusha:

https://backpack.tf/suggestion/5b968ee1cf6c7564cb70fb98

Screaming Tiger Rhythm Mini:

Sold for $34 and $30 on marketplace.tf

https://marketplace.tf/items/30921;5;u3006

http://manic.tf/keyprice/?at=2018-08-03 - $34 / $1.9 = 17.89 keys

http://manic.tf/keyprice/?at=2018-08-19 - $30 / $1.9 = 15.79 keys

X = 18

X = 16

Taking 17.

Other Sales:

https://backpack.tf/item/7040403438 (#1 & #2)

https://backpack.tf/item/6999123621 (#3-8)

https://backpack.tf/item/4883446503 (#10-14)

https://backpack.tf/item/4751026286 (#15)

https://backpack.tf/item/4702938292 (#16)

https://backpack.tf/item/4604509935 (#17 & 18)

https://backpack.tf/item/4231940848 (#19)

https://backpack.tf/item/4226672199 (#20 & #21)

https://backpack.tf/item/4219968799 (#22-24)

https://backpack.tf/item/4198679034 (#25)

https://backpack.tf/item/6864775845 (#26-29)

#1

Sold with ~4.5 keys in items for Purple Energy Trucker’s Topper

https://backpack.tf/profiles/76561198342476957#!/compare/1533686400/1533859200

https://backpack.tf/profiles/76561198226722604#!/compare/1533772800/1533859200

Should be used on the Trucker.

#2

Sold with ~7.5 keys in pure/items for Scorching Respectless Rubber Glove

https://backpack.tf/profiles/76561198226722604#!/compare/1533772800/1533859200

https://backpack.tf/profiles/76561198133015049#!/compare/1533772800/1533859200

Should be used on the Glove.

#3

Untraceable

https://backpack.tf/profiles/76561198312583107#!/compare/1532822400/1532908800

https://backpack.tf/profiles/76561198260146543#!/compare/1532822400/1532908800

https://i.imgur.com/yXVET9G.png - labelled as 32 keys, only 12 keys match here.

#4

Untraceable

https://backpack.tf/profiles/76561198287576576#!/compare/1533340800/1536624000

https://backpack.tf/profiles/76561198289062324#!/compare/1533254400/1533340800

#5

Untraceable

https://backpack.tf/profiles/76561198289062324#!/compare/1533340800/1533427200

https://backpack.tf/profiles/76561198337734785#!/compare/1533254400/1533340800

#6

Untraceable

https://backpack.tf/profiles/76561198337734785#!/compare/1533340800/1533427200

https://backpack.tf/profiles/76561198049112605#!/compare/1533081600/1533427200

#7

Untraceable, sold to scrap.tf

https://backpack.tf/profiles/76561198049112605#!/compare/1533945600/1534377600

https://backpack.tf/profiles/76561198135388328#!/compare/1534291200/1534377600

#8

Untraceable, bought from scrap.tf and dumped into “supercargo”.

https://backpack.tf/profiles/76561198135388328#!/compare/1534291200/1534377600

https://backpack.tf/profiles/76561198036445124#!/compare/1534291200/1534377600

#9

Untraceable

https://backpack.tf/profiles/76561198132520117#!/compare/1530057600/1531094400

https://backpack.tf/profiles/76561198337734785#!/compare/1531008000/1531094400

#10

Sold for Disco Beat Down Modest Metal Pile of Scrap + ~5.5 keys in taunts

https://backpack.tf/profiles/76561198260146543#!/compare/1532995200/1533081600

https://backpack.tf/profiles/76561198287576576#!/compare/1533081600/1533254400

Gonna be pretty high without a B/O cap.

#11

Untraceable

https://backpack.tf/profiles/76561198337734785#!/compare/1531094400/1531180800

https://backpack.tf/profiles/76561198080179568#!/compare/1531094400/1531180800

#12

Untraceable

https://backpack.tf/profiles/76561198080179568#!/compare/1533513600/1533600000

https://backpack.tf/profiles/76561198054002248#!/compare/1533427200/1533686400

#13

Untraceable

https://backpack.tf/profiles/76561198054002248#!/compare/1533772800/1535760000

https://backpack.tf/profiles/76561198820178900#!/compare/1533686400/1533772800

#14

Untraceable

https://backpack.tf/profiles/76561198820178900#!/compare/1533772800/1533859200

https://backpack.tf/profiles/76561198136995879#!/compare/1533772800/1533859200

#15

Untraceable

https://backpack.tf/profiles/76561198086948995#!/compare/1530576000/1530662400

https://backpack.tf/profiles/76561198185148093#!/compare/1530576000/1531526400

#16

Bulk for Pan

https://backpack.tf/profiles/76561198185148093#!/compare/1530489600/1530576000

https://backpack.tf/profiles/76561198192602363#!/compare/1530489600/1530576000

#17

Bulk for Cauldron Bubbles El Jefe

https://backpack.tf/profiles/76561198066516927#!/compare/1536019200/1536105600

https://backpack.tf/profiles/76561198075672562#!/compare/1535932800/1536105600

#18

Untraceable, most likely sold for keys

https://backpack.tf/profiles/76561198075672562#!/compare/1536451200/1536537600

https://backpack.tf/profiles/76561198132886814#!/compare/1536364800/1536451200

#19

Backpack purchase

https://backpack.tf/profiles/76561198075532147#!/compare/1529193600/1529280000

https://backpack.tf/profiles/76561198125791160#!/compare/1529193600/1529280000

#20

Sold with 9 keys for Disco Beat Down Cold Killer

https://backpack.tf/profiles/76561198081719047#!/compare/1532649600/1532736000

https://backpack.tf/profiles/76561198139831684#!/compare/1532563200/1532736000

Should be used on the Cold Killer.

#21

Untraceable

https://backpack.tf/profiles/76561198114001918#!/compare/1533081600/1536624000

https://backpack.tf/profiles/76561198337734785#!/compare/1533168000/1533254400

#22

Bulk for Death at Dusk Pirate Bandana

https://backpack.tf/profiles/76561198267589362#!/compare/1529884800/1529971200

https://backpack.tf/profiles/76561198158206236#!/compare/1529884800/1529971200

#23

Bulk for SBTWC Halogen

https://backpack.tf/profiles/76561198158206236#!/compare/1529971200/1530057600

https://backpack.tf/profiles/76561198303813920#!/compare/1529971200/1530057600

#24

Untraceable, seller’s backpack went private before it was scanned after the sale.

https://backpack.tf/profiles/76561198032176942#!/compare/1530057600/1530144000

#25

SCM

https://backpack.tf/profiles/76561197971910814#!/compare/1533254400/1533340800

https://backpack.tf/profiles/76561198080179568#!/compare/1533254400/1533340800

#26

Sold for Neutron Star Lil’ Bitey + ~1.5 keys in pure

https://backpack.tf/profiles/76561198102318448#!/compare/1528416000/1528848000

https://backpack.tf/profiles/76561198200802757#!/compare/1528761600/1528848000

Can be used on the Bitey.

#27

Untraceable, probably sold for keys

https://backpack.tf/profiles/76561198200802757#!/compare/1528848000/1528934400

https://backpack.tf/profiles/76561198062670918#!/compare/1528934400/1529020800

#28

Untraceable

https://backpack.tf/profiles/76561198209389815#!/compare/1532736000/1532822400

https://backpack.tf/profiles/76561198305676157#!/compare/1532736000/1532822400

https://i.imgur.com/yXVET9G.png - Labelled as a 27 key + 20 ref purchase

#29

Sold with other items to scrap.tf

https://backpack.tf/profiles/76561198418306144#!/compare/1534982400/1535241600

https://backpack.tf/profiles/76561198135388328#!/compare/1535155200/1535241600

Sellers:

https://i.imgur.com/5hrGJCY.png

https://backpack.tf/item/4604509935 - 37 keys

https://backpack.tf/item/4410341442 - 38 keys

https://backpack.tf/item/4702938292 - 38 keys

https://backpack.tf/item/4231940848 - 38 keys

Sales at:

22

25

27 (3x)

28 (2x)

29 (4x)

30 (3x)

33 (4x)

34

37

38

42

38 was a pure sale from almost 3 months ago, given the 2 and 3 month unsolds at 38, it should be safe to assume 38 and 42 are too high. Excluding 38 and 42.

With those excluded, 37 is also an outlier, given that it wasn’t pure, the B/O is missing (and may have been lower than the sale’s value), and the large amounts of sales for lower. Excluding 37.

Going with 28-37. Range suggested by Erik.