so many mini-suggestions... ;_;

Sale 1: (credits to Whoppers for the proof of sale)

Sold for 13 buds + 40 keys (40/14.75) + Black Paint ([2.25/14.75]*0.9) = 13 + 2.71 + 0.14 = 15.85 (rounding to 15.9)

http://www.tf2outpost.com/trade/23426608

http://imgur.com/a/9ZL8m

Sale 2: (credits to Whoppers for the proof of sale)

Sold for 6 buds + 10 keys (10/16.25) + Blizzard Viewfinder* (10.75*0.9) + Bill's Hat (4/16.25) = 6 + 0.62 + 9.675 + 0.25 = 16.545 (rounding to 16.5)

http://www.tf2outpost.com/trade/23058820

http://i.imgur.com/0bofD7c.png

Sale 3:

Sold for Scorching Barnstormer* (8.7*0.9) + Searing Wet Works* (3*0.9) + Max's Head (3.3) + Aussie Wrench (1.35*0.9) + 1 buds 7 keys (1 + [7/17]) = 7.83 + 2.7 + 3.3 + 1.215 + 1.41 = 16.455 (rounding to 16.5)

http://www.tf2outpost.com/trade/22851795

http://backpack.tf/profiles/76561198070061617?time=1411887600

Sale 4: (outlier)

Sold with 74 keys (74/14.75) + Ghastlierest Gibus Strangifier* ([8/14.75]*0.9) for Burning Rack (19.5*0.9)

? + 5.02 + 0.49 = 17.55 → ? = 12.04 (rounding to 12)

http://www.tf2outpost.com/trade/23707766

http://backpack.tf/profiles/76561198000112747?time=1416361337 → http://i.imgur.com/RuLCxGG.png

Sale 5:

Sold for 16 buds

http://www.tf2outpost.com/trade/22122227

Sale 6:

Sold for 16 buds

http://www.tf2outpost.com/trade/21374981

Mini for Blizzard Viewfinder:

http://www.tf2outpost.com/trade/22443324 - B/O at 10.5 buds (2 months)

http://www.tf2outpost.com/trade/23744732 - B/O at 11 buds (1 week)

~Valuing at 10.75 buds

Mini for Searing Wet Works:

http://www.tf2outpost.com/trade/23563192 - Sold for 3 buds

http://www.tf2outpost.com/trade/23481543 - Sold for P.Fetti Kabuto (outdated at 2.95)

~Valuing it at 3 buds

Mini for Scorching Barnstormer:

http://www.tf2outpost.com/trade/23270439 - Sold for PE Brainiac + 12 keys (outlier)

http://www.tf2outpost.com/trade/23200172 - Sold for DP Pullover* + ~1 in keys = ~8.7

~Valuing at 8.7 buds

Mini-mini for DP Pullover:

http://www.tf2outpost.com/trade/23284415 - B/O at 8 buds

http://www.tf2outpost.com/trade/23522638 - Quicksold for 83 keys = ~6

http://www.tf2outpost.com/trade/23727486 - Sold for ~9 in unusuals

~Valuing at 8.5 buds

Mini for Ghastlierest Gibus Strangifier:

Average sales on SCM, $18-19

~Valuing at 8 keys

Notes:

For valuing the buds, I'm using the price at the time of sale.

http://i.imgur.com/qmGoiZC.png - confirmation on items involved in Sale 1 & 2

http://www.tf2outpost.com/trade/23514906 - was willing to buy for 16 buds

http://i.imgur.com/KSBs009.png - B/O at 16 buds

Conclusion:

Sales at 15.9, 16.5, 16.5, 12, 16, 16. Valuing final range at 16-16.5. Sales at 17 clearly do not happen anymore.

Feel free to support/counter my suggestion!