Sale 1:

Sold for Stormy Storm Batter’s Helm (16)

No outpost

Seller: https://backpack.tf/profiles/76561198067214199#!/compare/1499731200/1499904000

Buyer: https://backpack.tf/profiles/76561198181076763#!/compare/1499817600/1499904000

X = 16

Sale 2:

Sold for Peace Sign Elfin’ Deal (13) + 2 keys + cosmetics (>0.5)

No outpost

Seller: https://backpack.tf/profiles/76561198181076763#!/compare/1500336000/1500422400

Buyer: https://backpack.tf/profiles/76561198127328235#!/compare/1500336000/1500422400

X = 16

Sale 3:

Sold for 13 keys + ~1 key in items

http://www.tf2outpost.com/trade/28894087 - B/O of 15

Seller: https://backpack.tf/profiles/76561198118621402#!/compare/1493683200/1493769600

Buyer: https://backpack.tf/profiles/76561198225960644#!/compare/1493683200/1493769600

X = 14

Sale 4:

Sold for 13 keys (Buyer’s compare link, 1 doesn’t match)

Seller: https://backpack.tf/profiles/76561198304138933#!/compare/1497484800/1497571200

Buyer: https://backpack.tf/profiles/76561198124832895#!/compare/1497398400/1497571200

X = 13

Sale 5:

Sold for Subatomic Head Full of Hot Air (12.5) + 1 key

http://www.tf2outpost.com/trade/28907286 - B/O of 13

Seller: https://backpack.tf/profiles/76561198225960644#!/compare/1493856000/1494028800

Buyer: https://backpack.tf/profiles/76561198042132655#!/compare/1493856000/1493942400

X = 13 (Capped by B/O

Sale 6:

Sold for 13 keys

Seller: https://backpack.tf/profiles/76561198054758757#!/compare/1497139200/1497225600

Buyer: https://backpack.tf/profiles/76561198196727109#!/compare/1497225600/1497657600

X = 13

Sale 7:

Sold for 12 keys + 15 ref

Seller: https://backpack.tf/profiles/76561198043940114#!/compare/1499990400/1500076800

Buyer: https://backpack.tf/profiles/76561198212868655#!/compare/1499731200/1500076800

Close enough to 13. Rounding up due to the other sales at 13.

X = 13

Sale 8:

Sold for Nuts n’ Bolts Blast Defense + 1 key

Seller: https://backpack.tf/profiles/76561198212868655#!/compare/1499731200/1500076800

Buyer: https://backpack.tf/profiles/76561198086793593#!/compare/1499990400/1500076800

Can be used to price the Blast.

Sale 9:

Sold with 2 keys for Green Confetti Fro

No outpost

Seller: https://backpack.tf/profiles/76561198086793593#!/compare/1499990400/1500076800

Buyer: https://backpack.tf/profiles/76561198061489334#!/compare/1499990400/1500076800

Sellers:

14 keys:

http://i.imgur.com/dODtcux.png

15 keys:

http://i.imgur.com/ndf2yAG.png

http://i.imgur.com/q4OnJjx.png

15.3 keys:

http://i.imgur.com/O0KQOrJ.jpg

16 keys:

http://i.imgur.com/ZEm8E7j.png - 5 days

http://i.imgur.com/FkgMSUR.png - 4 days

Sales at:

13 (4x)

14

16 (2x)

Excluding 16, as it looks like an outlier. If either of the sales were for pure, I’d include it.

Going with 13-14.