1 year old price!

Sale 1:

http://i.imgur.com/q85rdIm.png

Sale 2: (invalid sale; duped and outdated hats)

Sold with Planets Fed-Fightin' Fedora + KaW Soldered Sensei for Duped Sunbeams Le Party Phantom

http://www.tf2outpost.com/trade/25296416

http://backpack.tf/profiles/76561198063168204?time=1426143600 - before

http://backpack.tf/profiles/76561198063168204?time=1426230000 - after

http://i.imgur.com/q26VVvY.png

~If the other hats involved were to be updated, the value of the Miami Nights Desert Marauder would definitely end up being lower than the current price.

Sale 3:

Sold for TF Logo Crocleather Slouch (29*0.9) = 26.1 (rounding to 26 keys)

http://www.tf2outpost.com/trade/25582242

http://backpack.tf/profiles/76561198045572563?time=1429513200 - before

http://backpack.tf/profiles/76561198045572563?time=1429686000 - after

http://i.imgur.com/DdRqsCR.png

Sale 4: (invalid sale; outlier and outdated hat)

Sold for DBD Killer's Kabuto

http://www.tf2outpost.com/trade/25768392

http://backpack.tf/profiles/76561198059674109?time=1431586800 - before

http://backpack.tf/profiles/76561198059674109?time=1431673200 - after

http://i.imgur.com/WTl1Bb9.png

Mini-suggestion for Professional Strange Festive SMG*: (after tax)

Average value of $13.70 = ~5.5 keys

Notes:

http://www.tf2outpost.com/trade/25582242 - B/O of 30 keys

http://www.tf2outpost.com/trade/25296416 - B/O of 2.75 buds (~30 keys)

http://www.tf2outpost.com/trade/25276337 - B/O of 3 buds (~33 keys)

Conclusion:

One valid sales at 26 keys, alongside with B/Os revolving around ~30 keys. Taking a final price of 26 keys.

Feel free to support/counter my suggestion!