Using last month.

Sale 1:

Sold for 24 keys (Buyer’s end)

Seller: https://backpack.tf/profiles/76561198048563101#!/compare/1531526400/1531785600

Buyer: https://backpack.tf/profiles/76561198044353500#!/compare/1529452800/1531526400

Some keys went towards the strange pro. ks rocket launcher on the seller’s end before their backpack got scanned.

X = 24

Sales 2-4:

Sold for $38, $33.99, and $33 on marketplace.tf.

https://marketplace.tf/items/1162;5;u3004

38/1.99 = ~19.1

33.99/1.98 = ~17.2

33/1.98 = ~16.7

X = 19

X = 17 (2x)

Sale 5:

Sold for 18 keys

Seller: https://backpack.tf/profiles/76561198342161127#!/compare/1529971200/1530057600

Buyer: https://backpack.tf/profiles/76561198048563101#!/compare/1529884800/1530057600

X = 18

Sale 6:

Sold to a bot for 10 keys + 2 ref

Seller: https://backpack.tf/profiles/76561198087854567#!/compare/1531440000/1531699200

Buyer: https://backpack.tf/profiles/76561198312583107#!/compare/1531526400/1531612800

Bot.tf confirms: https://i.imgur.com/uanB9Vm.png

X = 10

Sellers:

24 keys:

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

https://backpack.tf/item/4410217794

30 keys:

https://i.imgur.com/JV2WQvt.png

https://backpack.tf/item/4441357495

95 keys:

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

https://backpack.tf/item/5776995558

Sales at:

10

17 (2x)

18

19

24

24 is an outlier, excluding 24.

10 is also an outlier, excluding.

Going with 17-19.

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

Cheaper sellers now, confirms 24 being high.