Let's try again?

Seller at 59, tried to sell it for month.

https://imgur.com/a/5EF4N

And sold it to mannco.trade.

https://imgur.com/a/dCpaK

Sales:

1.

50 pure

https://backpack.tf/profiles/76561198337734785#!/compare/1507248000/1507334400

And looks like previous owner sold it to Zol for 45

https://backpack.tf/profiles/76561198145247129#!/compare/1505606400/1506470400

He tried to sell it on MP before.

X1 = 50

--

2.

Sold with PRO Strange RL (~11) + PRO Strange Degreaser (~6.5) + Buds (2) for Green Black Hole Noble Amassment of Hats (81)

https://backpack.tf/profiles/76561198219084651#!/compare/1508976000/1509062400

X2 = 61

--

3.

With 5 keys for Disco Beat Down Dark Falkirk Helm (81)

https://backpack.tf/profiles/76561198190084707#!/compare/1508889600/1509062400

https://backpack.tf/profiles/76561198019257028#!/compare/1508976000/1509062400

X3 = 76

--

4.

Sold for Purple Energy Noble Amassment of Hats + 18 keys in items

https://backpack.tf/profiles/76561198219084651#!/compare/1507334400/1507420800

https://backpack.tf/profiles/76561198313791426#!/compare/1507161600/1507420800

[mini

Buyers at 50, seller at 55 (relisted, was 56)

Sales:

47 pure, QS

https://backpack.tf/profiles/76561198119634686#!/compare/1509580800/1509667200

-

Sold for pure, only 18 keys are shown here

https://backpack.tf/profiles/76561198107353742#!/compare/1508889600/1508976000

-

66 pure

https://backpack.tf/profiles/76561198179707937#!/compare/1506902400/1506988800

https://backpack.tf/profiles/76561198107353742#!/compare/1506902400/1507680000

-

Duped one was sold for DBD Gibus + 7 keys = 67

https://backpack.tf/profiles/76561198065957709#!/compare/1510444800/1510531200

https://backpack.tf/profiles/76561198114545227#!/compare/1510444800/1510531200

-

Scammers

https://backpack.tf/item/523738478

-

No idea

https://backpack.tf/profiles/76561198320858413#!/compare/1506816000/1507852800

https://backpack.tf/profiles/76561198344429943#!/compare/1506816000/1507420800

-

Taking 55 - 66 (~61 on avg)

]

61 + 18 = 79

X4 = 79

---

5.

Sold via Mannco.trade for 156 $, about 80 keys.

https://imgur.com/a/dCpaK

https://backpack.tf/item/5036318108

X5 = 80

------------------------------------------------------------------------------

Taking low-end based on pure sale at 50, and with the support of the unsuccesfull seller at 59

Taking high-end based on sale at ~79, rounding to an even number for good measure with the support of the mannco.trade's sale.