Re-suggesting, using last month.

Excluding all sales from the last suggestion that are now over a month old.

Sale 1:

Sold for 29 keys

Seller: https://backpack.tf/profiles/76561198344933095#!/compare/1522281600/1522368000

Buyer: https://backpack.tf/profiles/76561198017911489#!/compare/1522195200/1522368000

Confirmed by bot.tf stats: https://i.imgur.com/VgM5jp2.png

X = 29

Sale 2:

Sold for $50 on Marketplace.tf

https://marketplace.tf/items/1115;5;u3001

https://backpack.tf/item/4199237264

50/1.98 = ~25.25252525252525

X = 25

Sale 3:

Sold with a key for Tesla Coil Herald’s Helm (Mini at 19 below)

Seller: https://backpack.tf/profiles/76561197981054697#!/compare/1523750400/1523836800

Buyer: https://backpack.tf/profiles/76561198186710891#!/compare/1523750400/1523836800

X = 18

Tesla Coil Herald Mini:

Sale 1:

Sold for Max’s Head (~19)

Seller: https://backpack.tf/profiles/76561198171383322#!/compare/1523750400/1523836800

Buyer: https://backpack.tf/profiles/76561198186710891#!/compare/1523750400/1523836800

X = 19

Sale 2:

Sold for Terror-Watt Mann of Reason (Mini at 19.25 below)

Seller: https://backpack.tf/profiles/76561198125843156#!/compare/1516924800/1517097600

Buyer: https://backpack.tf/profiles/76561198113429637#!/compare/1517011200/1517097600

X = 19

Terror-Watt Mann Mini:

Sold for 20 keys

Seller: https://backpack.tf/profiles/76561198083800515#!/compare/1517097600/1517184000

Buyer: https://backpack.tf/profiles/76561198031389405#!/compare/1517097600/1517184000

X = 20

Aged seller at ~18.5 keys:

https://i.imgur.com/JZyOW9q.png

Taking 18.5-20 (19.25)

Sellers:

27 keys:

https://i.imgur.com/AAGQx6A.png

https://backpack.tf/item/6663329810

28 keys:

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

https://backpack.tf/item/4255056243

29 keys:

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

https://backpack.tf/item/2718388331

30 keys:

https://i.imgur.com/XSo7lPZ.png

https://backpack.tf/item/3827158524

80 keys:

https://i.imgur.com/96mJSL4.png

https://backpack.tf/item/2720659167

84 keys:

https://i.imgur.com/kORw2I1.png

https://backpack.tf/item/2690642332

90 keys:

https://i.imgur.com/zG84rUh.png

https://backpack.tf/item/3314858191

Sales at:

18

25

29

https://i.imgur.com/1epx2mF.png - Buyers at 18, excluding 18.

Going with 25-29.