Sold for Circling TF Logo Backbiter's Billycock (.9) + Strange Specialized Killstreak Australium Knife (1.42):

http://backpack.tf/profiles/76561198048498731?time=1417248000

http://backpack.tf/profiles/76561198048498731?time=1417334400

(1.42 + .9) * .9 = 2.088 buds

Rounded to 2.1 buds

Aussie Knife was 21 keys at the time. Buds were 14 keys.

[Sold for Haunted Phantasm Jr Bombing Run (1.73)]:

http://www.tf2outpost.com/trade/24513194

http://backpack.tf/profiles/76561198014412635?time=1420876800

http://backpack.tf/profiles/76561198014412635?time=1421508432

1.73 * .9 = 1.557 buds

Rounded to 1.6 buds

Supporting sale:

Sold with Blizzardy Storm Little Buddy (1) + Specialized Killstreak Big Kill (.9) for Searing Plasma Samur-Eye (4)]:

http://backpack.tf/profiles/76561198048498731?time=1417939200

http://backpack.tf/profiles/76561198048498731?time=1418025600

4 - .9 - 1 = 2.1 buds

Owner offered.

Supporting proof:

http://www.tf2outpost.com/trade/23623928

Got offered 1.8 buds