Sale 1:

Sold for 15 keys

http://www.tf2outpost.com/trade/28693834 - B/O of 15, re-listed multiple times

Seller: http://backpack.tf/profiles/76561198017852540#!/compare/1483142400/1483315200

Buyer: http://backpack.tf/profiles/76561198068294212#!/compare/1483228800/1483315200

X = 15

Sale 2:

Sold for Spec. KS Aussie Black Box (15)

No outpost

Seller: http://backpack.tf/profiles/76561198204824055#!/compare/1483315200/1483401600

Buyer: http://backpack.tf/profiles/76561198292296682#!/compare/1483315200/1483401600

X = 15

Sale 3:

Quicksold for 14 keys + 3 ref?

http://www.tf2outpost.com/trade/28694028 - B/O of 17

Seller: http://backpack.tf/profiles/76561198068294212#!/compare/1483315200/1483401600

Buyer: http://backpack.tf/profiles/76561198219020063#!/compare/1483228800/1483315200

X = 14

Sale 4:

Quicksold for 13 keys + Spec. KS Pan (1)

No outpost

Seller: http://backpack.tf/profiles/76561198128923241#!/compare/1483142400/1483315200

Buyer: http://backpack.tf/profiles/76561198204824055#!/compare/1483228800/1483315200

X = 14

Sale 5:

Sold for 13 keys + ~1 key in metal

http://www.tf2outpost.com/trade/28697497 - B/O of 16

Seller: http://backpack.tf/profiles/76561198254261991#!/compare/1483574400/1483660800

Buyer: http://backpack.tf/profiles/76561198018611790#!/compare/1483488000/1483660800

X = 14

Sellers:

18 keys:

http://i.imgur.com/l2IVy5l.png - 22 days

http://backpack.tf/u/76561198018611790

http://www.tf2outpost.com/trade/28709006

Sales at:

14 (3x)

15 (2x)

There is another one that doesn’t show when searching via premium search:

http://backpack.tf/item/5059185061 however, it has no usable sales.

(most) Sales at 14 quicksold. Excluding 14.

Going with 15 flat.