Sale 1:

Sold for 13 keys + <0.5 keys in metal/items

http://www.tf2outpost.com/trade/28845555 - B/O of 15.5

Seller: http://backpack.tf/profiles/76561198041219518#!/compare/1491782400/1491868800

Buyer: http://backpack.tf/profiles/76561198180885982#!/compare/1491782400/1491868800

X = 13

Sale 2:

Quicksold for 12 keys

No outpost

Seller: http://backpack.tf/profiles/76561198319715858#!/compare/1492041600/1492128000

Buyer: http://backpack.tf/profiles/76561198050518375#!/compare/1492041600/1492128000

X = 12

Sale 3:

Sold with ~5 keys in metal/items for Stormy Storm One-Man Army (14)

No outpost

Seller: http://backpack.tf/profiles/76561198068859240#!/compare/1495324800/1495411200

Buyer: http://backpack.tf/profiles/76561198054945991#!/compare/1495324800/1495411200

X = 9

Another sale:

Seller: http://backpack.tf/profiles/76561198304138933#!/compare/1496880000/1496966400

Buyer: http://backpack.tf/profiles/76561198190078474#!/compare/1496880000/1496966400

Unsure of how many keys it sold for. Definitely sold for keys, as it’s a bot, but the buyer’s compare link only shows 10 keys were involved, and I can guarantee that it sold for more than 10 keys.

Sellers:

15 keys:

http://i.imgur.com/CZOM6Dn.png - 22 days

http://backpack.tf/u/76561198054945991

http://www.tf2outpost.com/trade/29215361

Sales at:

9

12

13

12 quicksold. Excluding 12 and lower.

Going with 13 flat.