Sold for 2 buds + Aussie Rocket Launcher (4.8) + Stormy War Pig (2.7) + 20 keys in items (1.3) ~ 10.8 buds:

http://www.tf2outpost.com/trade/24569524

Sold for GE trilby (3.4) + Vivid honchos (3.6) + Searing Samureye (2.7, see current suggestion) ~ 9.7 buds:

http://backpack.tf/profiles/76561198007908851?time=1420963200 - after

http://backpack.tf/profiles/76561198007908851?time=1415865600 - before

Current seller(s):

http://www.tf2outpost.com/trade/23564972 - has a b/o of 10 buds

Since midpoint value is 10.25 buds (within 10-15 buds price range), rounding up to 10-11 buds.