Take 2.

Outdated price

Sale 1: ~16 keys pure

http://backpack.tf/profiles/76561198085465277#!/compare/1492905600/1493337600

Sale 2: Sold for Steaming Voodoo JuJu Slight Return (9) + 3 keys + Strange Hunter Heavy (1.5) --> 13.5; rounding to 14

http://backpack.tf/profiles/76561198085465277#!/compare/1495238400/1495324800

Mini Vooodo: ~9 keys pure http://backpack.tf/profiles/76561198106567078#!/compare/1494892800/1495584000

Sale 3: Sold for Green Confetti Industrial Festivizer (21.5) --> 22 keys

http://backpack.tf/profiles/76561198257750047#!/compare/1495411200/1495497600

Sale 4: 13 keys + 20 ref --> rounding to 14

http://backpack.tf/profiles/76561197982127154#!/compare/1493683200/1493769600

Has been actively advertised so not counting as QS http://www.tf2outpost.com/trade/28861698

Sale 5: Untraceable

http://backpack.tf/profiles/76561198232209392#!/compare/1492992000/1493164800

Sale 6: Bulk for Haunted Ghosts Your Worst Nightmare

http://backpack.tf/profiles/76561198206642680#!/compare/1493164800/1493337600

Sale 7: Sold together with 8 keys for Steaming Brainiac Hairpiece

Should be used to update the Brainiac

Sale 8: 15 keys pure

http://backpack.tf/profiles/76561198267173308#!/compare/1493769600/1493856000

Sale 9: Sold for Smoking Sergeant's Drill Hat (20) --> 20 keys

http://backpack.tf/profiles/76561198114635132#!/compare/1495584000/1495670400

Sale 10: Untraceable

http://backpack.tf/profiles/76561198294088256#!/compare/1494547200/1494806400

Sales at: 14, 14, 15, 16, 20, 22

Multiple unsolds below 20

http://i.imgur.com/EXZ1MQc.png

Suggesting range from 14-16; calling 20 & 22 high.

Thanks to sin for his feedback on the range in my previous suggestion.