Very outdated price range. You can't even buy it for 6 buds now.

http://www.tf2outpost.com/trade/7688946 - Knifestorm Tyrolean (7.9), Burning Crown (7.2), Lantern Dragonborn (6.7), GE Kabuto + bills (6.4), Ghost Hallmark + Max (6.8), 8 pure, 7 pure

http://www.tf2outpost.com/trade/2499274 - Scorching Baker + 2 buds (8.4), two 7 pure offers, 6 pure + sweets offer, 7 pure + white bill offer, GE Kabuto + bills (6.4), Scorching Hot dogger + Burning Buckaroo + Bubbling Grimm hatte (7.8), Burning Geisha + Peace Beak + Bubbling Beak (8)

In conslusion, 8 buds would be good as high end since some people are offering 8 pure or 8 buds in unusual, and it looks most of the offers are between 6.4 ~ 8. So this range seems good now.