Old suggestion

http://backpack.tf/suggestion/5903ed0d0e2cad1807003229

Sale 1: 16 keys pure

http://backpack.tf/profiles/76561198332812722#!/compare/1493337600/14934240

Screenshotted in case the keys move today. http://i.imgur.com/NhSYtHI.png

Sale 2: Sold together with a Cloud 9 Magniciant Mongolian (10.5) for an Orbiting Fire Modest Pile (27.5) --> 17 keys

http://backpack.tf/profiles/76561198047593891#!/compare/1491264000/1491350400

Mini for C9 Mongolian: 10.5 keys http://backpack.tf/profiles/76561198076417722#!/compare/1492905600/1492992000

Sale 3: 14 keys pure; was quicksell. Flyu2015 told me himself; --> not eligible

http://backpack.tf/profiles/76561198332812722#!/compare/1493164800/1493337600

Sale 4 (New): 18 Keys pure

http://backpack.tf/profiles/76561198259942392#!/compare/1493337600/1493424000

http://i.imgur.com/h2H1QHE.png

Suggesting a range from 16-18 keys here