Sale #1:

http://www.tf2outpost.com/trade/26023344

Sold for Specialized Aussie RL (56) + Pro KS S. Powerjack (~6) + ~1 key in other items

Seller:

http://backpack.tf/profiles/76561198137880575?time=1432882800 (May 29th)

http://backpack.tf/profiles/76561198137880575?time=1433228400 (June 2nd) - http://i.imgur.com/Td77Up7.png

Buyer:

http://backpack.tf/profiles/76561198096299803?time=1432882800 (May 29th)

http://backpack.tf/profiles/76561198096299803?time=1433142000 (June 1st)

http://www.tf2outpost.com/trade/26061675 Rocket Launcher

There was a sale in between this one which was 1:1 with Specialized Aussie RL with another person, but it appears to have been traded back.

(56 + 6 + 1) * 0.9 = 56.7; rounded to 57 keys

Sale #2:

http://www.tf2outpost.com/trade/25815375

Sold for Smoking Valhella Helm (18) + Strange Headtaker (~20) + TS Bill's (2.5)

http://backpack.tf/profiles/76561198095821025?time=1430118000 (April 27th)

http://backpack.tf/profiles/76561198095821025?time=1430204400 (April 28th)

Seems to have sold very quick. This would be very low.

Sale #3:

Sold for a Heart Batter's Helmet + 4 keys

http://backpack.tf/profiles/76561198095821025?time=1430636400 (May 3rd)

http://backpack.tf/profiles/76561198095821025?time=1430722800 (May 4th)

Can't be used, the Trophy Belt was used to price the Batter's Helmet.

Sale #4:

http://www.tf2outpost.com/trade/25813672

Sold for 59 keys + ~1 in items

http://backpack.tf/profiles/76561198086948995?time=1432882800 (May 29th)

http://backpack.tf/profiles/76561198086948995?time=1432969200 (May 30th) - http://i.imgur.com/jIK5xy5.png

59 + 1 = 60 keys

Sale #5:

http://www.tf2outpost.com/trade/25926733

Sold with 6 keys for a Ghosts Swagman's (50) + SF Rocket Launcher (18)

http://backpack.tf/profiles/76561198095022730?time=1432018800 (May 19th)

http://backpack.tf/profiles/76561198095022730?time=1432450800 (May 24th)

A Strange Huntsman was bought after the trade, the other 4 keys can be tracked here:

http://backpack.tf/profiles/76561197969363424?time=1432018800 (May 19th)

http://backpack.tf/profiles/76561197969363424?time=1432105200 (May 20th)

((50 + 18) * 0.9) - 6 = 55.2; rounded to 55 keys

Sale #6:

Sold with a MN Festivizer + gifted KaW Front Runner + Pro KS SF Ubersaw for an Australium Flame Thrower

http://backpack.tf/profiles/76561198083171063?time=1429426800 (April 19th)

http://backpack.tf/profiles/76561198083171063?time=1429513200 (April 20th)

Maybe other items or cash were involved, I don't know. This would be very low.

Specialized Aussie RL:

http://www.tf2outpost.com/trade/26010436 Sold for 56 keys