9.

1 of 2.

WHOA.

Sale 1: http://backpack.tf/profiles/76561198058156238#!/compare/1490659200/1490918400 / http://backpack.tf/item/5645865285

Sold for a Clean Miami Nights Condor Cap (70 keys) + a Clean Stormy Storm Cotton Head (88 keys) + 9 pure

70 + 88 + 9 = 167 (either this isnt the sale, this is a shark or simply the biggest outlier i have seen so far).

Sale 2: http://backpack.tf/profiles/76561198042018679#!/compare/1491177600/1491264000

Sold for a Clean Ancient Codex A Head Full of Hot Air (14 keys) + a Clean Infernal Flames Taunt: Bucking Bronco (50 keys)

50 + 14 = 64

Mini for Bronco: http://backpack.tf/suggestion/58ed2222c44045155e6ecb84

Additional proof by polar:

http://www.tf2outpost.com/trade/28856891 - b/o 45

http://backpack.tf/profiles/76561198096389539#!/compare/1487203200/1487289600 - sold for 45 pure

http://backpack.tf/profiles/76561198175466147#!/compare/1487203200/1487289600 - immediately after it was traded for the spellbound ~55

Going with a range of 45-65.