Mind Bender

http://backpack.tf/item/1688904819

Sale 1) Sold for a Vivid Plasma Hustler's Hallmark (42.5 Keys)

http://backpack.tf/profiles/76561198090457223/#!/compare/1455696000/1455782400

Rounding to 43 Keys

Sale 2) Sold for a Green Black Hole Backbiter's Billycock (42 Keys) + 1 Key in Items

http://backpack.tf/profiles/76561198008485821/#!/compare/1456128000/1456300800

42 + 1 = 43 Keys

This sale is still usable, because the Billycock was priced with a different sale that also was worth 42 Keys.

Sale 3) Sold for a Duped PE Trilby

http://backpack.tf/profiles/76561198084168091/#!/compare/1456128000/1456214400

http://www.tf2outpost.com/trade/27883074 - Capped by the Buyout of 41 Keys