Try #4. Sale at 31 is now older than 3 months, which lets me call 27 an outlier. Three usable sales in the end.

Sale 1: Cash? Buyer's side doesn't show any other items either.

http://backpack.tf/profiles/76561198120467518#!/compare/1484179200/1484265600

[Excluding]

Sale 2: Cash...again? Nothing added, hat removed.

http://backpack.tf/profiles/76561198152277166#!/compare/1487894400/1488067200

[Excluding]

Sale 3: EXPIRED

Buyer: http://backpack.tf/profiles/76561198049112605#!/compare/1484870400/1485734400

This one was a puzzle. 'DanTheLadiesMan' buys and sells 2 different copies of this hat on the same day.

Bought for Smoking Scotch Bonnet (15-16, 2 years ago) + Skill Gotten Gains Spent Well Spirits (18-19, in-date)

Smoking Bonnet mini: Unsold at 12.5 for 29 days, taking 12.5. Buyers at 10.5 support.

http://tinypic.com/r/1zvd3za/9

12.5 + 18.5 = 31

[No longer using: >3 months old]

Sale 4:

http://backpack.tf/profiles/76561198128276213#!/compare/1489104000/1489190400

P.fetti Patriot Peak (68-80, 8 months ago) + GE Heralds (unpriced) = Steaming Bonk (24-31, in-date) + X + Slumber Wraith Wrap (46, in-date)

Patriot mini:

http://www.tf2outpost.com/search/269987443 A couple unsold at 70 for 2 weeks or more.

Maybe used for GE Herald?

[Excluding]

Sale 5: Hard to say; snapshots too far apart. Looks like nothing.

http://backpack.tf/profiles/76561198049112605#!/compare/1484870400/1485734400

[Excluding]

Sale 6:

seller: http://backpack.tf/profiles/76561198049112605#!/compare/1487203200/1488153600

buyer: http://backpack.tf/profiles/76561198128276213#!/compare/1488067200/1488153600

Pretty screwy compares for one reason or another, I don't think everything is showing up correctly.

Appears to be a 1:1 with a K.Watt Whoopee (24, 2 years ago)

Whoopee mini:

Couple buyers at 13.

http://backpack.tf/profiles/76561198213714427#!/compare/1486425600/1486512000

For Aussie knife, about 16. Taking 16.

[Taking 16, excluding as outlier]

Sale 7:

http://backpack.tf/profiles/76561198263243336#!/compare/1488153600/1488240000

Bought for a G.Fetti Crocleather (14-15, in-date) + PE Ol' Geezer (32, 4 months ago)

Just one day after previous sale.

PE Geezer mini:

26 pure: http://backpack.tf/profiles/76561198115478183#!/compare/1490400000/1490486400

31 pure: http://backpack.tf/profiles/76561198277396732#!/compare/1487635200/1488067200

Quickbuyer(s) at 25 uphold the sale for 31.

X = 14.5 + 31 = 45.5

B/O of 50 does not cap this. http://www.tf2outpost.com/trade/28803637

[Taking 45]

Sale 8:

http://backpack.tf/profiles/76561198317146471#!/compare/1488412800/1488499200

Sold for a Spectral Swirl Carlton (unpriced) + 2 keys

Does not help that 'gingasnaps' sold 2 of these hats within a day

Spectral Swirl Carlton mini:

http://www.tf2outpost.com/trade/28647433 Unsold at 50 for 3 months

Buyer for 22.

http://backpack.tf/profiles/76561198196627443#!/compare/1489104000/1489190400

Sold for Screaming Tiger Deep Fried (40, in-date)

http://backpack.tf/profiles/76561198239598834#!/compare/1491004800/1491091200

Bought for C.Heart Fancy Fedora (54-55, 4 months ago)

http://backpack.tf/profiles/76561198253605675#!/compare/1490572800/1490745600

Sold for Stormy Storm Executioner (28, 4 months ago) + 2 keys

Taking 40;

40 + 2 = 42

[Taking 42]

Sale 9:

http://backpack.tf/profiles/76561198081073113#!/compare/1489104000/1489190400

Sold for Mystery to Everyone Hellmet (45-50, a year ago) + S.Pro Big Earner (2 ish)

Mystery to Everyone Hellmet mini:

Quickbuyer at 29, http://tinypic.com/r/23jpjyu/9

Sale: http://backpack.tf/profiles/76561197976524938#!/compare/1488758400/1488844800

Sold for Logo Dapper's Topper (45, in-date)

However, it had a b/o of 40: http://www.tf2outpost.com/trade/28818851

Taking 40

One listed on outpost by 'Zero Beat' http://www.tf2outpost.com/user/17264 at about 50 for 3 months.

40 + 2 = 42

[Taking 42]

Sale 10:

http://backpack.tf/profiles/76561198094744576#!/compare/1489190400/1489363200

Sold with MW Pink Elephant Sticky (1 ish) + 3 keys for Ghastly Ghosts Jr Tartan Spartan (29-32, in-date)

X = 30.5 - 1 - 3 = 26.5 = 27

[Taking 27, excluding as outlier]

Sale 11:

http://backpack.tf/profiles/76561198115699456#!/compare/1492214400/1492300800

Spelled logo capo's (13-16, 5 months ago) + 2 + SF.pro spy-cicle (1.8)

Without the spell this is about 17 keys. Looks to be a low outlier.

B/O was 43, so possibly other stuff was added? http://www.tf2outpost.com/trade/28842763

[Excluding]

Sales of 16*, 27*, 31*, 42, 42, and 45.

Unsold at 50 keys for 2 months.

Final range: 42-45.

Any corrections, suggestions, or advice is appreciated.