Sale 1:

Sold for 12 keys

Seller: https://backpack.tf/profiles/76561198148511293#!/compare/1546905600/1546992000

Buyer: https://backpack.tf/profiles/76561198404491245#!/compare/1546905600/1546992000

https://backpack.tf/item/2483543401

X = 12

Sale 2:

Sold for 11 keys + 5 ref?

Seller: https://backpack.tf/profiles/76561198315588518#!/compare/1550966400/1551052800

Buyer: https://backpack.tf/profiles/76561198129339403#!/compare/1551052800/1551139200

https://backpack.tf/item/7026590890

https://i.imgur.com/eE7LpdG.png

Only 8 keys + 5 ref match, but I doubt there’s much more to this sale. I don’t doubt that it was exactly 11 keys + 5 ref, 3 of the keys being spent on something else on the same day.

X = 11

Sale 3:

Sold for 10 keys + 7 ref

Seller: https://backpack.tf/profiles/76561198221009364#!/compare/1549152000/1549411200

Buyer: https://backpack.tf/profiles/76561198427851737#!/compare/1549238400/1549411200

https://backpack.tf/item/2365838168

X = 10

Sale 4:

Sold for 10 keys

Seller: https://backpack.tf/profiles/76561198427851737#!/compare/1549670400/1550016000

Buyer: https://backpack.tf/profiles/76561198139800274#!/compare/1549756800/1550016000

https://backpack.tf/item/2365838168

X = 10

Sale 5:

Sold for 9 keys + 15 ref

Seller: https://backpack.tf/profiles/76561198404491245#!/compare/1546905600/1546992000

Buyer: https://backpack.tf/profiles/76561198083134207#!/compare/1546905600/1546992000

https://backpack.tf/item/2483543401

X = 9.5

Sale 6:

Sold for 9 keys + 12.55 ref

Seller: https://backpack.tf/profiles/76561198148843171#!/compare/1552176000/1552262400

Buyer: https://backpack.tf/profiles/76561198349886701#!/compare/1552176000/1552262400

https://backpack.tf/item/3246170718

Several items sold to the same buyer on the same day, so it’s hard to tell what he was paying, but bot.tf listings reveal he was paying 9 keys + 12.55 ref

https://bot.tf/stats/listings/46KQ0VR4

X = 9.5

Sale 7:

Sold to a quickbuyer for 9 keys + 11 ref

Seller: https://backpack.tf/profiles/76561198129339403#!/compare/1550707200/1551052800

Buyer: https://backpack.tf/profiles/76561198083134207#!/compare/1550966400/1551052800

https://backpack.tf/item/7026590890

X = 9

Sale 8:

Sold for 9 keys

Seller: https://backpack.tf/profiles/76561198148836514#!/compare/1550361600/1550448000

Buyer: https://backpack.tf/profiles/76561198167304451#!/compare/1550361600/1550448000

https://backpack.tf/item/2365838168

X = 9

Sale 9:

Sold for 9 keys + Buy a Life

Seller: https://backpack.tf/profiles/76561198079756509#!/compare/1549065600/1549152000

Buyer: https://backpack.tf/profiles/76561198221009364#!/compare/1549065600/1549152000

https://backpack.tf/item/2365838168

X = 9

Other Sales:

https://backpack.tf/item/7026590890 (#1 & #2)

https://backpack.tf/item/4081452812 (#3)

https://backpack.tf/item/3246170718 (#4 & #5)

https://backpack.tf/item/2483543401 (#6-9)

https://backpack.tf/item/2365838168 (#10-16)

#1

Untraceable

https://backpack.tf/profiles/76561198134429694#!/compare/1548460800/1548547200

https://backpack.tf/profiles/76561198315588518#!/compare/1548460800/1548547200

https://i.imgur.com/eE7LpdG.png - Labelled as 9 keys + 5 ref

#2

Untraceable

https://backpack.tf/profiles/76561198315588518#!/compare/1549411200/1549497600

https://backpack.tf/profiles/76561198832832186#!/compare/1549238400/1549497600

https://i.imgur.com/eE7LpdG.png - Labelled as 11 keys + 5 ref

Also sold back to the seller on the same day, in the same links above. Labelled as 9 keys + 5 ref.

#3

SCM

https://backpack.tf/profiles/76561198346054736#!/compare/1546819200/1548028800

https://backpack.tf/profiles/76561198334451855#!/compare/1551312000/1551398400

#4

Untraceable

https://backpack.tf/profiles/76561198256958866#!/compare/1552089600/1552262400

https://backpack.tf/profiles/76561197961805093#!/compare/1551484800/1552089600

#5

Sold for Smoking Airdog

https://backpack.tf/profiles/76561198142755528#!/compare/1552176000/1552262400

https://backpack.tf/profiles/76561198148843171#!/compare/1552176000/1552262400

#6

Untraceable

https://backpack.tf/profiles/76561198083134207#!/compare/1547078400/1547164800

https://backpack.tf/profiles/76561198373295660#!/compare/1546905600/1547164800

#7

Untraceable

https://backpack.tf/profiles/76561198373295660#!/compare/1547164800/1548374400

https://backpack.tf/profiles/76561198083134207#!/compare/1547251200/1547337600

#8

Untraceable

https://backpack.tf/profiles/76561198083134207#!/compare/1549065600/1549152000

https://backpack.tf/profiles/76561198855343697#!/compare/1548979200/1549152000

#9

SCM

https://backpack.tf/profiles/76561198855343697#!/compare/1549238400/1549324800

https://backpack.tf/profiles/76561198371651326#!/compare/1549411200/1549497600

#10

Sold for Purple Confetti Fat Man’s Field Cap

https://backpack.tf/profiles/76561198025361452#!/compare/1548979200/1549152000

https://backpack.tf/profiles/76561198079756509#!/compare/1549065600/1549152000

#11

Untraceable

https://backpack.tf/profiles/76561198139800274#!/compare/1550361600/1550448000

https://backpack.tf/profiles/76561198148836514#!/compare/1550275200/1550361600

#12

Untraceable

https://backpack.tf/profiles/76561198167304451#!/compare/1550361600/1550448000

https://backpack.tf/profiles/76561198224448340#!/compare/1550448000/1550534400

#13

Untraceable

https://backpack.tf/profiles/76561198224448340#!/compare/1550448000/1550534400

https://backpack.tf/profiles/76561198105669852#!/compare/1550448000/1550534400

#14

Untraceable

https://backpack.tf/profiles/76561198105669852#!/compare/1550448000/1550534400

https://backpack.tf/profiles/76561198083134207#!/compare/1550361600/1550448000

#15

Untraceable

https://backpack.tf/profiles/76561198105669852#!/compare/1550448000/1550534400

https://backpack.tf/profiles/76561198083134207#!/compare/1550361600/1550448000

#16

Untraceable

https://backpack.tf/profiles/76561198083134207#!/compare/1550707200/1550793600

https://backpack.tf/profiles/76561198873183784#!/compare/1550448000/1550793600

Sellers:

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

https://backpack.tf/item/3246170718 - ~10.5 keys

https://backpack.tf/item/7026590890 - ~10.5 keys

Sales at:

9 (3x)

9.5 (2x)

10 (2x)

11

12

9 is far too common to be excluded, despite quickbuyers. Also worth noting that there are the 2 untraceable purchases at 9 keys that would support this. Keeping 9.

12 is looking like an outlier, given current sellers and how commonly it sold for less. The sale is also pretty old compared to the now shifted market. Had there have been a second sale at 12, or had the sale been more recent, I would’ve kept 12 in the range. Excluding 12.

Going with 9-11.