Sale 1:

Sold for 17 keys

http://www.tf2outpost.com/trade/28523195 - B/O of 17

Seller: http://backpack.tf/profiles/76561198021055079#!/compare/1475712000/1475798400

Buyer: http://backpack.tf/profiles/76561198196587222#!/compare/1475625600/1475884800

http://i.imgur.com/K1wx0PN.png

http://i.imgur.com/UcX2meO.jpg

X = 17

Sale 2:

Sold for 16 keys

http://www.tf2outpost.com/trade/28400293 - B/O of 16

Seller: http://backpack.tf/profiles/76561198021055079#!/compare/1470614400/1470700800

Buyer: http://backpack.tf/profiles/76561198095655100#!/compare/1467504000/1471046400 (unhelpful link)

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

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

Sale 3:

Sold for Steaming Swagman’s Swatter (Outdated, however, buyer at 10) + Genuine Pro. KS AWPer Hand (6)

http://www.tf2outpost.com/trade/28396021 - B/O of 17

Seller: http://backpack.tf/profiles/76561198192602363#!/compare/1471219200/1471305600

Buyer: http://backpack.tf/profiles/76561198114491802#!/compare/1470614400/1471305600

The steaming Swagman’s has a buyer at 10, which would prove 10 to be too low. Therefore, this sale should cap at the B/O

X = 17 (Capped by B/O)

Sale 4:

Sold for Orbiting Fire Detective Noir (Outdated, however, buyer at 15) + 1 key

http://www.tf2outpost.com/trade/28525783 - B/O of 16, seller confirms sale (legend)

Seller: http://backpack.tf/profiles/76561198016583076#!/compare/1475798400/1475884800

Buyer: http://backpack.tf/profiles/76561198048616739#!/compare/1475798400/1475884800

With the buyer at 15 for the noir, 15 would be too low of a price for it. Therefore, the sale would cap at the B/O

X = 16 (Capped by B/O)

Sellers:

25 keys:

http://backpack.tf/u/76561198066352194

http://www.tf2outpost.com/trade/28537014 - young

Sales at:

17 (2x)

16 (2x)

Paid 14 keys for it both times, once from my buy order, once from a seller

Going with 16-17