9 month old price!

Sale 1:

Sold for Aces High Your Worst Nightmare* (37*0.9) = 33.3 (rounding to 33 keys)

http://www.tf2outpost.com/trade/24737648

http://backpack.tf/profiles/76561198117451303?time=1429513200 (20th April)

http://backpack.tf/profiles/76561198117451303?time=1429686000 (22nd April)

Sale 2: (was used to price the toe)

Sold for Demonflame Stately Steel Toe

http://www.tf2outpost.com/trade/25747984

http://backpack.tf/profiles/76561198114269795?time=1429772400 (23rd April)

http://backpack.tf/profiles/76561198114269795?time=1429858800 (24th April)

Sale 3: (support-sale, bandana is outdated)

Sold for Cloud 9 Burning Bandana (34*0.9) = 30.6 (rounding to 31 keys)

http://www.tf2outpost.com/trade/25785460

http://backpack.tf/profiles/76561198052984141?time=1430118000 (27th April)

http://backpack.tf/profiles/76561198052984141?time=1430809200 (5th May)

Mini-suggestion for Aces High Your Worst Nightmare*:

http://www.tf2outpost.com/trade/25762590 - B/O of 37 keys for more than a week

Notes:

http://www.tf2outpost.com/trade/24737648 - B/O of 34 keys

http://i.imgur.com/ncJ1Ofj.png - B/O of 35 keys (has had it for ~5 months)

Conclusion:

One valid sale at 33 keys and a support-sale at 31 keys, along with B/Os at 34-35 keys. Taking a final price of 33 keys.

Feel free to support/counter my suggestion!