Sale 1:

Sold for 2 keys + ~12 keys in items

No outpost

Seller: https://backpack.tf/profiles/76561198351299890#!/compare/1508544000/1508630400

Buyer: https://backpack.tf/profiles/76561198375961156#!/compare/1508371200/1508630400

X = 14

Sale 2 & 3:

Sold for $23.89 and $23.99 on Marketplace.tf

https://marketplace.tf/items/158;5;u29

23.89/2 = ~11.9

23.99/2 = ~12

X = 12 (2x)

Sale 4:

Sold for 10 keys + at least 17.11 ref (Buyer’s compare link)

Seller: https://backpack.tf/profiles/76561198359394527#!/compare/1509926400/1510012800

Buyer: https://backpack.tf/profiles/76561198065409820#!/compare/1509926400/1510012800

X = 11

Sale 5:

Sold for Miami Nights Sober Stuntman

http://www.tf2outpost.com/trade/29439791 - B/O of 11

Seller: https://backpack.tf/profiles/76561198135959895#!/compare/1510531200/1511222400

Buyer: https://backpack.tf/profiles/76561198328467289#!/compare/1511222400/1511308800

Should easily cap.

X = 11 (Capped by B/O)

Sale 6:

Sold for Terror-Watt Hive Minder + ~1.5 keys in items

http://www.tf2outpost.com/trade/29455456 - B/O of 10.5

Seller: https://backpack.tf/profiles/76561198004952793#!/compare/1511481600/1511568000

Buyer: https://backpack.tf/profiles/76561198238151258#!/compare/1511481600/1511568000

Easily caps.

X = 11 (Capped by B/O)

Sale 7:

Sold for 9 keys + 20 ref

Seller: https://backpack.tf/profiles/76561198355490842#!/compare/1509753600/1509926400

Buyer: https://backpack.tf/profiles/76561198124597793#!/compare/1509753600/1509926400

X = 10

Sale 8:

Sold for 9 keys + 25 ref

Seller: https://backpack.tf/profiles/76561198304138933#!/compare/1511913600/1512000000

Buyer: https://backpack.tf/profiles/76561198000420937#!/compare/1511827200/1512086400

X = 10

Sale 9:

Sold for 9 keys + at least half a key worth of ref

Seller: https://backpack.tf/profiles/76561198304138933#!/compare/1512691200/1512777600

Buyer: https://backpack.tf/profiles/76561198257066953#!/compare/1512345600/1512777600

X = 10

Sale 10:

Sold for 9 keys + 20 ref

Seller: https://backpack.tf/profiles/76561198304138933#!/compare/1512086400/1512172800

Buyer: https://backpack.tf/profiles/76561198258319074#!/compare/1512172800/1512259200

X = 10

Sale 11:

Sold for Spec. KS Aussie FaN (~9) + Black Rose Spec. KS Kit (~1)

http://www.tf2outpost.com/trade/29452037 - B/O of 11

Seller: https://backpack.tf/profiles/76561198327326803#!/compare/1511049600/1511308800

Buyer: https://backpack.tf/profiles/76561198059859203#!/compare/1511222400/1511308800

X = 10

Sale 12:

Quicksold for 9 keys + cheap items

Seller: https://backpack.tf/profiles/76561198140161915#!/compare/1511568000/1511654400

Buyer: https://backpack.tf/profiles/76561198271428863#!/compare/1511568000/1511654400

X = 9

Sale 13:

Quicksold for 9 keys

Seller: https://backpack.tf/profiles/76561198203537236#!/compare/1511913600/1512000000

Buyer: https://backpack.tf/profiles/76561198187474697#!/compare/1511913600/1512000000

X = 9

Sale 14:

Sold for Blizzardy Storm Bonk Helm

No B/O’s on outpost

Seller: https://backpack.tf/profiles/76561198125791160#!/compare/1509148800/1509235200

Buyer: https://backpack.tf/profiles/76561198273843317#!/compare/1508976000/1509753600

Don’t wanna use without a B/O.

Sale 15:

Sold with B.M.O.C for Ghastly Ghosts Shred Alert

Seller: https://backpack.tf/profiles/76561198065409820#!/compare/1510272000/1510358400

Buyer: https://backpack.tf/profiles/76561198059690074#!/compare/1422172800/1510358400

Should be used on the taunt, if not too low there.

Sale 16:

Bulk for Purple Energy Stout Shako

Seller: https://backpack.tf/profiles/76561198071983249#!/compare/1511568000/1511654400

Buyer: https://backpack.tf/profiles/76561198160856661#!/compare/1511568000/1511654400

Sale 17:

Sold with ~1 key in items for Orbiting Fire Scotch Bonnet

Seller: https://backpack.tf/profiles/76561198085037135#!/compare/1511481600/1511568000

Buyer: https://backpack.tf/profiles/76561198004952793#!/compare/1511481600/1511568000

Can be used on the Bonnet.

Sale 18:

Sold for Spectral Swirl Battin’ a Thousand

Seller: https://backpack.tf/profiles/76561198152387915#!/compare/1510358400/1510444800

Buyer: https://backpack.tf/profiles/76561198070068553#!/compare/1506384000/1510444800

Can be used on the taunt.

Sale 19:

Sold with 2 keys for Miami Nights Hive Minder

Seller: https://backpack.tf/profiles/76561198201046166#!/compare/1507852800/1507939200

Buyer: https://backpack.tf/profiles/76561198161393800#!/compare/1507852800/1507939200

Should be used on the Hive.

Sale 20:

Sold for Orbiting Fire Janissary Ketche + 1 key

No outpost

Seller: https://backpack.tf/profiles/76561198091179527#!/compare/1511740800/1511827200

Buyer: https://backpack.tf/profiles/76561198092509893#!/compare/1511827200/1511913600

Should easily fit into the range.

Sale 21:

Sold with a key worth of items for Logo Sultan’s Ceremonial

Seller: https://backpack.tf/profiles/76561198092509893#!/compare/1511827200/1511913600

Buyer: https://backpack.tf/profiles/76561198347317315#!/compare/1511827200/1511913600

Can be used on the Sultan.

Sale 22:

Bulk for DBD Madame Dixie

Seller: https://backpack.tf/profiles/76561198095360309#!/compare/1510358400/1510531200

Buyer: https://backpack.tf/profiles/76561198093253104#!/compare/1510444800/1510531200

Sale 23:

Sold with 2 keys for Kill-a-Watt Gentleman’s Gatsby

No outpost

Seller: https://backpack.tf/profiles/76561198127084057#!/compare/1509840000/1509926400

Buyer: https://backpack.tf/profiles/76561198359394527#!/compare/1509926400/1510012800

Will be too high if used here, and too low if used on the Gatsby. Excluding this sale.

Sellers:

10 keys:

https://i.imgur.com/dVqGzZC.png - 6 days

~10.3 keys:

https://i.imgur.com/fmApSJF.png - young

~10.8 keys:

https://i.imgur.com/CnvlhzC.png - 2x

11 keys:

https://i.imgur.com/RnndfzT.png - 10 days

12 keys:

https://i.imgur.com/9pwb1Wu.png - 2 months

Sales at:

9 (2x)

10 (5x)

11 (3x)

12 (2x)

14

14 is an outlier. Excluding 14.

9 is countered by quickbuyers, and quicksold anyways. Excluding 9.

Going with 10-12.