Just copying over some other in date sales from the last rejected suggestion:

Sold for green energy milkman, steaming sergeant's drill hat and specialized strange frying pan = ~53 keys

http://www.tf2outpost.com/trade/26410940

Seller before: http://backpack.tf/profiles/76561198061836787?time=1437462000 (July 21st)

Seller after: http://backpack.tf/profiles/76561198061836787?time=1437548400 (July 22nd)

http://www.tf2outpost.com/trade/26489227 Sold for Haunted Ghost Samur-Eye

More sales:

http://www.tf2outpost.com/trade/26489227 - ghosts samur (mini at 48.5 * 0.9 = ~44)

http://backpack.tf/profiles/76561198100514826?time=1439017200

http://backpack.tf/profiles/76561198100514826?time=1439103600

http://www.tf2outpost.com/trade/26676977 - sold for Time Warp Bubble Pipe (48.5 * 0.9 = ~44)

http://backpack.tf/profiles/76561198079349621?time=1442041200

http://backpack.tf/profiles/76561198079349621?time=1442386800 - sold with MW Hot Aqua Marine Rocket Launcher for MG War Pig?

A quick mini on the Samur (48-49):

http://backpack.tf/profiles/76561198040902095?time=1440831600

http://backpack.tf/profiles/76561198040902095?time=1440918000

http://www.tf2outpost.com/trade/26914841 - sold for beams tricorne (barely still at 55 at the time, 55 * 0.9 = ~49)

http://backpack.tf/profiles/76561198146795212?time=1440226800

http://backpack.tf/profiles/76561198146795212?time=1440399600

http://www.tf2outpost.com/trade/26852695 - sold for PE tavish crown (very barely outdated at 51, who cares) + 2 keys = (51 * 0.9 = 46) + 2 = 48

So yeah, this is actually really close. I'm countering at 44 though, as the pure sale is just too old and I need this for another suggestion.