Sale 1:

Sold for $69.99 on Marketplace.tf

https://marketplace.tf/items/30006;5;u107

https://backpack.tf/item/5193297353

69.99/1.97 = ~35.53

X = 36

Sale 2:

Sold for Peace Sign Human Cannonball (25.5)

http://www.tf2outpost.com/trade/29375206 - B/O of 20

Seller: https://backpack.tf/profiles/76561198313509123#!/compare/1506038400/1506124800

Buyer: https://backpack.tf/profiles/76561198092291231#!/compare/1505779200/1506124800

X = 20 (Capped by B/O)

Sale 3:

Sold for 18 keys

Seller: https://backpack.tf/profiles/76561198394877897#!/compare/1507334400/1507420800

Buyer: https://backpack.tf/profiles/76561198094878213#!/compare/1507161600/1507420800

X = 18

Sale 4:

Sold for 17 keys in ~10 days (ID’s match)

Seller: https://backpack.tf/profiles/76561198002757046#!/compare/1507939200/1508025600

Buyer: https://backpack.tf/profiles/76561198066584736#!/compare/1507939200/1508025600

X = 17

Sale 5:

Sold for 17 keys + 14 ref in ~2 days

Seller: https://backpack.tf/profiles/76561198106233311#!/compare/1505779200/1505865600

Buyer: https://backpack.tf/profiles/76561198313509123#!/compare/1505779200/1505865600

X = 17

Sale 6:

Sold with Voodoo JuJu for Electrostatic Scotsman’s Stove Pipe

Seller: https://backpack.tf/profiles/76561197964478868#!/compare/1508803200/1510617600

Buyer: https://backpack.tf/profiles/76561198192602363#!/compare/1508716800/1508803200

Should be used on the Stove.

Sellers:

20 keys:

https://i.imgur.com/JtDJvav.png - 2 days

22 keys:

https://i.imgur.com/IXwLvk9.png - 1 month

Sales at:

17 (2x)

18

20

36

Sale at 36 is quite clearly an outlier. Excluding 36.

One sale at 17 days took 2 days, while the other took 10. Gonna keep 17 in the range.

Going with 17-20.