Recently became outdated, so I'm updating it with some new sales.

Sale #1:

http://www.tf2outpost.com/trade/21590922 - Sold for a SBTWC Bone Dome (5.2 x .9 = ~4.7)

http://backpack.tf/profiles/76561198037271140?time=1406703600 - Seller's backpack before

http://backpack.tf/profiles/76561198037271140?time=1406876400 - Seller's backpack after

Sale #2:

http://www.tf2outpost.com/trade/21555573 - Sold for a Showstopper Meet the Medic Taunt (~4.7, no overpay because offered on)

http://backpack.tf/profiles/76561198008170993?time=1406444400 - Seller's backpack before

http://backpack.tf/profiles/76561198008170993?time=1406530800 - Seller's backpack after

Sale #3 (Quicksale):

http://www.tf2outpost.com/trade/21527949 - Sold for a clean Max's and 19 keys (4, calling this a quicksale because it sold for pure B/O in 2 days)

http://backpack.tf/profiles/76561198064443270?time=1406358000 - Seller's backpack before

http://backpack.tf/profiles/76561198064443270?time=1406444400 - Seller's backpack after

Sale #4 (Outlier):

http://www.tf2outpost.com/trade/21273530 - Sold for a Burning Flames Sultan's Ceremonial (4.5 x .9 = ~4.2)

However, AA owner added 6 keys and a black Bills Hat, so sale is ultimately valued at ~3.6.

Calling this an outlier because of the above quicksell for 4 pure.

http://backpack.tf/profiles/76561198120637329?time=1406271600 - Seller's backpack before

http://backpack.tf/profiles/76561198120637329?time=1406358000 - Seller's backpack after

http://backpack.tf/profiles/76561198064443270?time=1406358000 - Buyer's backpack after (more clearly demonstrates what was added)

Currently on Outpost:

http://www.tf2outpost.com/trade/19408975 - B/O of 6.5

http://www.tf2outpost.com/trade/21543409 - B/O of 5

http://www.tf2outpost.com/trade/21683789 - No B/O

Updating the price to 4.7 flat.

If you have any constructive criticisms for my suggestion, let me know and I'll try to fix it.