Sale 1:

Sold for Haunted Ghosts Shooter’s Sola Topi (17.5) + ~3.5 keys in items

http://www.tf2outpost.com/trade/29387440 - Deleted B/O

Seller: https://backpack.tf/profiles/76561198114402400#!/compare/1507248000/1507334400

Buyer: https://backpack.tf/profiles/76561198134923092#!/compare/1507334400/1507680000

X = 21

Sale 2:

Sold for Strange Logo Tin Topi (Mini at 17 below) + ~4 keys in items

http://www.tf2outpost.com/trade/29446014 - No B/O

Seller: https://backpack.tf/profiles/76561198255903931#!/compare/1510876800/1510963200

Buyer: https://backpack.tf/profiles/76561198000288933#!/compare/1498953600/1510963200

X = 21

Sale 3:

Sold for Strange Pro. KS Festive Flamethrower (12)

Seller: https://backpack.tf/profiles/76561198366738890#!/compare/1505692800/1505779200

Buyer: https://backpack.tf/profiles/76561198157862949#!/compare/1505520000/1505692800

X = 12

Sale 4:

Bulk for Logo Mohawk

Seller: https://backpack.tf/profiles/76561198133912681#!/compare/1506038400/1506124800

Buyer: https://backpack.tf/profiles/76561198114402400#!/compare/1506038400/1506124800

Sale 5:

Sold with 2 keys for Stormy Storm Reggaelator

Seller: https://backpack.tf/profiles/76561198134923092#!/compare/1510704000/1510790400

Buyer: https://backpack.tf/profiles/76561198302759439#!/compare/1510617600/1510790400

Seems pretty damn low. Excluding.

Strange Logo Tin Topi Mini:

Sold for Disco Beat Down Conquistador (Suggestion at 17)

http://www.tf2outpost.com/trade/29446641 - No B/O

Seller: https://backpack.tf/profiles/76561198255903931#!/compare/1510963200/1511049600

Buyer: https://backpack.tf/profiles/76561198067086447#!/compare/1510790400/1511049600

Disco Beat Down Conquistador:

https://backpack.tf/suggestion/5a2a87a6cf6c753eb95636db

Sellers:

18 keys:

https://i.imgur.com/13SDtps.png - 8 days

Sales at:

12

21 (2x)

12 is way too low. Excluding 12.

Seller at 18.

Going with 18-21.