Despite the links not being sold, it shows that sellers are willing to ask for half the suggest value of the current price of around a key, and yet they still aren't sold, so maybe the price is even less.

http://www.tf2outpost.com/trade/6047073 - asking for 1.66 Didn't want a range of 0.66 ref though, thought it might be too large.

http://www.tf2outpost.com/trade/6013988 - sold for 2.33, most likely an outlier since most are unsold.

http://www.tf2outpost.com/trade/6083053 - wants 2 refined

http://www.tf2outpost.com/user/71358 - 1 offer of 1 refined, 1 week ago

http://tf2tp.com/trade.php?trade=8596606 - wants 1 ref, tradepost isn't that reliable on prices since not many people use it

Here's tons of people asking for 2.33 refined - 2.66 / 1 key, and I've now checked whether they're in the seller's bp or not

http://www.tf2outpost.com/trade/5915804 - 2.66 ref, 4 days ago, no offers,

http://www.tf2outpost.com/trade/5956099 - backpack.tf prices, 4 days ago, no offers on the Fallen Angel

http://www.tf2outpost.com/trade/6073815 - 2.66, 18 hours ago, no offers

http://www.tf2outpost.com/trade/5797365 - 1 key B/O, 1 week ago, no offers on the Fallen Angel

http://www.tf2outpost.com/trade/5762344 - 1 key, 1 week ago, no offers on the Fallen Angel

http://www.tf2outpost.com/trade/5757125 - 1 key, 1 week ago, no offers on the Fallen Angel

http://www.tf2outpost.com/trade/6062391 - 2.33, 1 day ago, no offers. Seems to be new to Outpost

http://www.tf2outpost.com/trade/5892710 - "spreadsheet prices" i.e. 1 key, no offers on the Fallen Angel

http://www.tf2outpost.com/trade/5952905 - 1 key + 0.55, overcharging for set, 4 days ago, no offers on the set or individual pieces

http://www.tf2outpost.com/trade/5858940 - 1 key or Haunted Pyro soul (which you can get for like 1 reclaimed), 6 days ago, no offers.

http://www.tf2outpost.com/trade/5931803 - wants 2 keys for it (lol), 4 days ago - got a decent offer of 2 refined but declined

There's a few more on pages 5-6 also asking for a key, but they're inactive people. All these results were from searching for a Haunted Fallen Angel

The first commented link asking for 1.66 is now asking for 1 refined, finally got a taker for it.

The user link was supposed to be for this trade - http://www.tf2outpost.com/trade/5685693

The person asking for 2 refined had a previous trade 3 days ago asking for 2.33 refined, but no luck - http://www.tf2outpost.com/trade/6024382