Using last month.

Sale 1:

Sold for 4 keys + 20 ref

Seller: https://backpack.tf/profiles/76561198340634356#!/compare/1549584000/1549670400

Buyer: https://backpack.tf/profiles/76561198356520490#!/compare/1549584000/1549670400

https://backpack.tf/item/6420632541

https://i.imgur.com/n1vrjC8.png - bot.tf confirms

X = 4.5

Sale 2:

Sold to a bot for 3 keys + 20 ref

Seller: https://backpack.tf/profiles/76561198362414257#!/compare/1547596800/1547856000

Buyer: https://backpack.tf/profiles/76561198363395191#!/compare/1547510400/1547596800

https://backpack.tf/item/6791712326

X = 3.5

Other Sales:

https://backpack.tf/item/6791712326 (#1)

https://backpack.tf/item/6672186104 (#2)

https://backpack.tf/item/6277802358 (#3)

https://backpack.tf/item/5527876419 (#4)

https://backpack.tf/item/7288799097 (#5)

https://backpack.tf/item/7218438005 - scrap

https://backpack.tf/item/6629673195 - scrap

https://backpack.tf/item/6708729356 - transferred between bots

https://backpack.tf/item/5403977551 - gambled

#1

Untraceable

https://backpack.tf/profiles/76561198363395191#!/compare/1548633600/1548720000

https://backpack.tf/profiles/76561198072898758#!/compare/1548633600/1549670400

gambled afterwards

#2

Untraceable

https://backpack.tf/profiles/76561198044335614#!/compare/1548720000/1548806400

https://backpack.tf/profiles/76561198106441454#!/compare/1548720000/1548806400

gambled afterwards

#3

SCM

https://backpack.tf/profiles/76561198083891688#!/compare/1548547200/1549584000

https://backpack.tf/profiles/76561198153336088#!/compare/1548115200/1548633600

#4

Untraceable

https://backpack.tf/profiles/76561198227829944#!/compare/1548720000/1549584000

https://backpack.tf/profiles/76561198079155814#!/compare/1548633600/1548720000

#5

Sold for Fountain of Delight Soldier’s Requiem

https://backpack.tf/profiles/76561198350879574#!/compare/1549238400/1549324800

https://backpack.tf/profiles/76561198318385717#!/compare/1549065600/1549411200

The requiem currently has buyers higher than the sellers on the fubar. Would be best to exclude this sale.

Sellers:

https://i.imgur.com/7QlKgeG.png

https://backpack.tf/item/6708729356 - ~4.5 keys

https://backpack.tf/item/6659210828 - ~4.5 keys

https://backpack.tf/item/4966132263 - 7 keys

Sales at:

3.5

4.5

The sale at 3.5 is the only one that went to a quickbuyer in the last month. I wouldn’t call it a common trading point. Excluding 3.5.

Going with 4.5 flat.