Sale 1:

Sold for 18 keys

Seller: https://backpack.tf/profiles/76561198053252981#!/compare/1507939200/1508025600

Buyer: https://backpack.tf/profiles/76561198380872881#!/compare/1507939200/1508025600

X = 18

Sale 2:

Sold for 16 keys (IDs match)

Seller: https://backpack.tf/profiles/76561198394877897#!/compare/1508889600/1508976000

Buyer: https://backpack.tf/profiles/76561198083126313#!/compare/1508284800/1508976000

X = 16

Sale 3:

Sold for 16 keys (IDs match)

No outpost

Seller: https://backpack.tf/profiles/76561198394877897#!/compare/1506643200/1506729600

Buyer: https://backpack.tf/profiles/76561198154537737#!/compare/1502841600/1506729600

X = 16

Sale 4:

Quicksold for 15 keys

Seller: https://backpack.tf/profiles/76561198197287330#!/compare/1506556800/1506643200

buyer: https://backpack.tf/profiles/76561198060458887#!/compare/1506556800/1506643200

X = 15

Sale 5:

Quicksold for 15 keys

Seller: https://backpack.tf/profiles/76561198060458887#!/compare/1506556800/1506643200

Buyer: https://backpack.tf/profiles/76561198248967314#!/compare/1506470400/1506643200

X = 15

Sale 6:

Quicksold for 15 keys

Seller: https://backpack.tf/profiles/76561198248967314#!/compare/1506643200/1506729600

Buyer: https://backpack.tf/profiles/76561198130662205#!/compare/1506643200/1506729600

X = 15

Sale 7:

Sold with painted cosmetics for Vivid Plasma Buckaroo’s Hat

Seller: https://backpack.tf/profiles/76561198135982067#!/compare/1506211200/1506297600

Buyer: https://backpack.tf/profiles/76561198053252981#!/compare/1506211200/1506297600

Can be used on the Vivid one.

Sale 8:

Bulk for Darkblaze Bootleg Base Metal Billycock

Seller: https://backpack.tf/profiles/76561198154537737#!/compare/1507248000/1507334400

Buyer: https://backpack.tf/profiles/76561198267189538#!/compare/1507248000/1507334400

Sale 9:

Bulk for Green Confetti Bonk Boy

Seller: https://backpack.tf/profiles/76561198042391041#!/compare/1506556800/1506643200

Buyer: https://backpack.tf/profiles/76561198197287330#!/compare/1506556800/1506643200

Sales at:

15 (3x)

16 (2x)

18

No current sellers.

Sales at 15 are common, so I’ll keep it in the range.

Going with 15-18.