Sale 1:

Sold for Vivid Plasma Sergeant’s Drill Hat (38)

Seller: https://backpack.tf/profiles/76561198047025682#!/compare/1552953600/1553040000

Buyer: https://backpack.tf/profiles/76561198061716132#!/compare/1552953600/1553040000

https://backpack.tf/item/5749031765

X = 38

Sale 2:

Sold for Terror-Watt Shellmet (Suggestion at 29) + 7 keys

Seller: https://backpack.tf/profiles/76561198370703651#!/compare/1548201600/1548288000

Buyer: https://backpack.tf/profiles/76561198370703651#!/compare/1548201600/1548288000

https://backpack.tf/item/6050048411

X = 36

Sale 3:

Sold for Disco Beat Down Nuke (35)

Seller: https://backpack.tf/profiles/76561198150307915#!/compare/1551830400/1551916800

Buyer: https://backpack.tf/profiles/76561198348057478#!/compare/1551830400/1551916800

https://backpack.tf/item/7329795797

X = 35

Sale 4:

Sold for 30 keys

Seller: https://backpack.tf/profiles/76561198137642054#!/compare/1551657600/1551830400

Buyer: https://backpack.tf/profiles/76561198150307915#!/compare/1551744000/1551830400

https://backpack.tf/item/7329795797

X = 30

Sale 5:

Sold for 30 keys

Seller: https://backpack.tf/profiles/76561198002757046#!/compare/1552089600/1552176000

Buyer: https://backpack.tf/profiles/76561198118983738#!/compare/1552089600/1552176000

https://backpack.tf/item/5749031765

X = 30

Sale 6:

Sold for 20 keys + Double-spelled Backstabber’s Boomslang (Mini at 10 below)

Seller: https://backpack.tf/profiles/76561198176297517#!/compare/1552953600/1553040000

Buyer: https://backpack.tf/profiles/76561198047025682#!/compare/1552953600/1553040000

https://backpack.tf/item/5749031765

X = 30

Sale 7:

Sold with ~2 keys in items for Time Warp Prancer’s Price (31)

Seller: https://backpack.tf/profiles/76561198167304451#!/compare/1552521600/1552608000

Buyer: https://backpack.tf/profiles/76561198258264645#!/compare/1552435200/1552521600

https://backpack.tf/item/5749031765

X = 29

Sale 8:

Sold for 28 keys + 22 ref

Seller: https://backpack.tf/profiles/76561198258264645#!/compare/1552608000/1552694400

Buyer: https://backpack.tf/profiles/76561198176297517#!/compare/1552608000/1552694400

https://backpack.tf/item/5749031765

X = 28

Sale 9:

Sold to a quickbuyer for 28 keys

Seller: https://backpack.tf/profiles/76561198370703651#!/compare/1548547200/1548979200

Buyer: https://backpack.tf/profiles/76561198056793444#!/compare/1548806400/1548979200

https://backpack.tf/item/6050048411

X = 28

Marketplace Sales:

https://marketplace.tf/items/30542;5;u7

https://manic.tf/keyprice/?at=2018-12-26 - $69 / $1.81 = 38.12 keys

https://manic.tf/keyprice/?at=2019-02-15 - $60 / $1.8 = 33.33 keys

X = 38

X = 33

Other Sales:

https://backpack.tf/item/5749031765 (#1-4)

https://backpack.tf/item/7537260360 - mannco

https://backpack.tf/item/7028724096 - scrap

#1

Untraceable

https://backpack.tf/profiles/76561198129230935#!/compare/1552003200/1552089600

https://backpack.tf/profiles/76561198002757046#!/compare/1552003200/1552089600

#2

Sold with 4 keys for Electrostatic Fez

https://backpack.tf/profiles/76561198118983738#!/compare/1552089600/1552176000

https://backpack.tf/profiles/76561198119559226#!/compare/1552089600/1552176000

Would be better to update the Fez with this sale, given how overpriced it is (and how likely it is to be lacking sales that aren’t gambling).

#3

Sold with 10 keys for Ancient Eldritch Neptune’s Nightmare

https://backpack.tf/profiles/76561198119559226#!/compare/1552176000/1552262400

https://backpack.tf/profiles/76561198105071091#!/compare/1552176000/1552262400

Should be used on the Nightmare

#4

Bulk for Scorching Chullo

https://backpack.tf/profiles/76561198105071091#!/compare/1552435200/1552521600

https://backpack.tf/profiles/76561198167304451#!/compare/1552435200/1552521600

Terror-Watt Shellmet:

https://backpack.tf/suggestion/5c98b394d381722c1d6e9a07

Double-spelled snek:

https://backpack.tf/profiles/76561198176297517#!/compare/1553212800/1553299200 - Sold for 10 keys

Sellers:

https://i.imgur.com/Wtt9a6O.png

https://backpack.tf/item/7028724096 - 37 keys

https://backpack.tf/item/7331247514 - 38 keys

https://backpack.tf/item/6050048411 - 39 keys

https://backpack.tf/item/6052995873 - 40 keys

https://backpack.tf/item/7193412393 - 40 keys

Sales at:

28 (2x)

29

30 (3x)

33

35

36

38 (2x)

https://i.imgur.com/2vQM2Aj.png - Buyers at 28 keys, excluding 28.

Going with 29-38.