Sold with ~4 keys for Green Energy Prince Tavish's Crown (3.7):

http://backpack.tf/profiles/76561198019734628?time=1421568000

http://backpack.tf/profiles/76561198019734628?time=1421781854

http://www.tf2outpost.com/trade/24707712

http://www.tf2outpost.com/trade/24742276

3.7 * .9 - 4 / 13 = 3.0223 buds

Rounded to 3 buds

Sold for duped Eerie Orbiting Fire Scotsman's Stove Pipe (3.2):

http://www.tf2outpost.com/trade/24661066

http://www.tf2outpost.com/trade/24743309

3.2 buds

Mini for duped Eerie Stove Pipe:

Rounded to 3.2 buds

Sold for Time Warp Front Runner?

http://www.tf2outpost.com/trade/24742252

http://www.tf2outpost.com/trade/24745733

Sold with 4 keys + ~1.5 keys in items for Australium Grenade Launcher (25 keys):

http://i.gyazo.com/13f9eddb68dd9789529a0105d1903320.png

http://i.gyazo.com/61c392ffd230d8ed8fd3189351ace31c.png

Outlier. I have received offers around 2 buds.