Sale 1:

Sold for $33.51 on Marketplace.tf

https://marketplace.tf/items/465;5;u35

https://backpack.tf/item/2749412053

33.51/1.99 = ~16.8

X = 17

Sale 2:

Sold for ~18 keys in items

http://www.tf2outpost.com/trade/29389987 - B/O of 15

Seller: https://backpack.tf/profiles/76561198045466865#!/compare/1507420800/1507507200

Buyer: https://backpack.tf/profiles/76561198101325132#!/compare/1507420800/1507507200

X = 15 (Capped by B/O)

Sale 3:

Sold for Stormy Storm Hustler’s Hallmark (Suggestion at 14.5)

http://www.tf2outpost.com/trade/29429317 - B/O of 13

Seller: https://backpack.tf/profiles/76561198118602098#!/compare/1510012800/1510099200

Buyer: https://backpack.tf/profiles/76561198047401076#!/compare/1510012800/1510099200

X = 13

Sale 4:

Sold for 12 keys + probably more metal than what appears here

Seller: https://backpack.tf/profiles/76561198304138933#!/compare/1509494400/1509580800

Buyer: https://backpack.tf/profiles/76561198118602098#!/compare/1509494400/1509753600

The bot is selling another one for ~12.8 keys, so I’m fairly certain that the sale was closer to ~12.8 keys. Either way, fits in the range.

X = 12 or 13

Sale 5:

Sold for 12 keys + cheap items

Seller: https://backpack.tf/profiles/76561198134266699#!/compare/1510617600/1510704000

Buyer: https://backpack.tf/profiles/76561198084447725#!/compare/1510617600/1510704000

X = 12

Sale 6:

Bulk for stuff

Seller: https://backpack.tf/profiles/76561198386817983#!/compare/1510444800/1512000000

Buyer: https://backpack.tf/profiles/76561198093438754#!/compare/1510358400/1510444800

Sale 7:

Sold for Whirlwind Bad Pipes

Seller: https://backpack.tf/profiles/76561198131395072#!/compare/1509926400/1510012800

Buyer: https://backpack.tf/profiles/76561198046777197#!/compare/1510012800/1510099200

Should be used on Bad Pipes.

Sale 8:

Sold with ~2 keys in items for Circling Heart Football Helmet

Seller: https://backpack.tf/profiles/76561198046777197#!/compare/1510099200/1510185600

Buyer: https://backpack.tf/profiles/76561198122028802#!/compare/1509926400/1510185600

Probably best not to use on either end of the trade, would be too high for the football helmet (if it doesn’t cap at a B/O), and too small here.

Stormy Hallmark:

https://backpack.tf/suggestion/5a253484cf6c7550907b65a8

Sellers:

12.8 keys:

https://i.imgur.com/5lRzGJe.png - 3 days

13.2 keys:

https://i.imgur.com/joVCrTn.png - 4 days

https://backpack.tf/item/575173584 - owned for ~15 days

Sales at:

12

13

15

18

And another sale at 12-13.

18 looks like a large outlier. Excluding 18.

Going with 12-15.