Using last month.

Sale 1:

Sold for 5 keys

Seller: https://backpack.tf/profiles/76561198097271466#!/compare/1564185600/1564272000

Buyer: https://backpack.tf/profiles/76561198156266720#!/compare/1532476800/1564272000

https://backpack.tf/item/6644489477

X = 5

Sale 2:

Sold for 4 keys + 23.22 ref?

Seller: https://backpack.tf/profiles/76561198056803716#!/compare/1562284800/156288600

Buyer: https://backpack.tf/profiles/76561198841279602#!/compare/1562198400/1562284800

https://backpack.tf/item/6252791907

23.22 ref on the seller’s end, 3 keys on the buyer’s end.

https://bot.tf/stats/listings/MX9LV8PY - bot was buying for 4 keys + 23.22 ref at the time of the sale, I’m certain it sold for that amount.

X = 4.5

Other Sales:

https://backpack.tf/item/7748035267 (#1 & #2)

https://backpack.tf/item/7440301627 (#3)

https://backpack.tf/item/6874293722 (#4 & #5)

https://backpack.tf/item/6458429272 (#6)

https://backpack.tf/item/6384503619 (#7)

https://backpack.tf/item/6309399826 (#8)

https://backpack.tf/item/6280127068 (#9 & #10)

https://backpack.tf/item/6322229040 - marketplace

https://backpack.tf/item/7449766098 - scrap/gambled

https://backpack.tf/item/6506394024 - all backpack transfers or something

Marketplace Sales:

https://marketplace.tf/items/tf2/1183;5;u3003

$9.15, Jul 4th

$11, Jul 6th

$9.15, Jul 12th

$9.15, Jul 15th

$9.10, Jul 15th

$9.10, Jul 16th

https://manic.tf/keyprice/?at=2019-07-04 - $9.15 / $1.84 = 4.97 keys

https://manic.tf/keyprice/?at=2019-07-06 - $11 / $1.85 = 5.95 keys

https://manic.tf/keyprice/?at=2019-07-12 - $9.15 / $1.83 = 5.00 keys

https://manic.tf/keyprice/?at=2019-07-15 - $9.15 / $1.83 = 5.00 keys

https://manic.tf/keyprice/?at=2019-07-15 - $9.10 / $1.83 = 4.97 keys

https://manic.tf/keyprice/?at=2019-07-16 - $9.1 / $1.82 = 5.00 keys

X = 6

X = 5 (5x)

#1

Untraceable

https://backpack.tf/profiles/76561198246419486#!/compare/1556928000/1562630400

https://backpack.tf/profiles/76561198951043019#!/compare/1562112000/1562716800

Didn’t bother with the sale before this as it wasn’t even visible on either compare link

#2

Untraceable

https://backpack.tf/profiles/76561198951043019#!/compare/1562889600/1562976000

https://backpack.tf/profiles/76561198342161127#!/compare/1562803200/1562889600

#3

SCM

https://backpack.tf/profiles/76561198131192033#!/compare/1561420800/1562630400 (no good compare)

https://backpack.tf/profiles/76561198005875727#!/compare/1562976000/1563148800

#4

Untraceable

https://backpack.tf/profiles/76561198305676157#!/compare/1562025600/1562112000

https://backpack.tf/profiles/76561197967874961#!/compare/1562025600/1562112000

https://i.imgur.com/bRnghiT.png - Labelled as 5 keys + 42 ref (~6 keys)

Gambled afterwards.

#5

Untraceable

https://backpack.tf/profiles/76561198066742724#!/compare/1562371200/1562889600

https://backpack.tf/profiles/76561198340634356#!/compare/1562803200/1562889600

https://i.imgur.com/bRnghiT.png - Labelled as 4 keys + 32 ref (~4.5 keys)

#6

Untraceable

https://backpack.tf/profiles/76561198061836787#!/compare/1562112000/1562198400

https://backpack.tf/profiles/76561198228259444#!/compare/1562025600/1562630400

#7

Untraceable

https://backpack.tf/profiles/76561198144879030#!/compare/1562716800/1562976000

https://backpack.tf/profiles/76561198047852423#!/compare/1562716800/1562803200

#8

Untraceable

https://backpack.tf/profiles/76561198186718459#!/compare/1563148800/1563321600

https://backpack.tf/profiles/76561198340634356#!/compare/1563148800/1563235200

https://i.imgur.com/bRnghiT.png - labelled as a 4 key + 32 ref purchase (~4.5 keys)

Gambled prior

#9

Untraceable

https://backpack.tf/profiles/76561198105098440#!/compare/1562544000/1562716800

https://backpack.tf/profiles/76561198950294215#!/compare/1562630400/1562716800

#10

Untraceable

https://backpack.tf/profiles/76561198148021922#!/compare/1563235200/1563321600

https://backpack.tf/profiles/76561198305676157#!/compare/1563235200/1563321600

https://i.imgur.com/bRnghiT.png - labelled as a 4 key + 22 ref purchase (~4.5 keys)

Gambled prior

Additionally, here are the entire bot.tf stats for this item, given it has sold a lot in the last 3 months:

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

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

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

As we can see, older purchases and sales are higher than current sellers/sales, which supports my decision to exclude anything older than a month.

Sellers:

https://i.imgur.com/iiNcfT7.png

https://backpack.tf/item/6252791907 - ~4.9 keys

https://backpack.tf/item/6320691056 - 5 keys

https://backpack.tf/item/6874293722 - ~5.2 keys

https://backpack.tf/item/7662286166 - ~5.7 keys

https://backpack.tf/item/6280127068 - ~5.8 keys

Sales at:

4.5

5 (6x)

6

All sellers are less than 6 keys, excluding 6.

Going with 4.5-5.