Sellers:

https://marketplace.tf/items/30360;5;u61

https://backpack.tf/item/5154538694 - b/o: $39 = 19 keys

http://www.tf2outpost.com/trade/29208610 - b/o: 16 keys (2 weeks)

http://www.tf2outpost.com/trade/29221266 - b/o: 13 keys (1 week)

Sold:

https://backpack.tf/profiles/76561198134797815#!/compare/1496880000/1496966400

https://backpack.tf/profiles/76561198173442901#!/compare/1496793600/1496880000 - sold for ? (quicksold)

https://backpack.tf/profiles/76561198134797815#!/compare/1496793600/1496880000 - ?

https://backpack.tf/profiles/76561198304138933#!/compare/1496707200/1496793600 - sold for 9 keys (low)

http://www.tf2outpost.com/trade/28869382

https://backpack.tf/profiles/76561198256934643#!/compare/1493164800/1493510400

https://backpack.tf/profiles/76561198121731353#!/compare/1493078400/1493164800 - sold with 1 key + 43 ref for Steaming Towering Pillar of Hats (16) = 14 keys

https://backpack.tf/profiles/76561198152483690#!/compare/1491696000/1491782400

https://backpack.tf/profiles/76561198256934643#!/compare/1491696000/1491782400 - sold for Tesla Coil Cranial Carcharodon (15) = 15 keys

https://backpack.tf/profiles/76561198048571227#!/compare/1491436800/1491523200 - bulk

Mini’s:

Steaming Towering Pillar of Hats:

https://backpack.tf/suggestion/59466682c44045104873d778 = 16 keys

Conclusion:

sales at 9, 14, 15

sellers at 13, 16, 19

taking 13-15 keys