http://www.tf2outpost.com/trade/7830057 - Bought one for 3 ref.

http://www.tf2outpost.com/trade/7681893 - Sold for "low end of backpack.tf prices"

http://www.tf2outpost.com/trade/7849899 - Sold for 3 ref

http://www.tf2outpost.com/trade/4771182 - Sold for 3 ref

http://www.tf2outpost.com/trade/7468175 - Accepted an offer for 3 ref

http://www.tf2outpost.com/trade/6486073 - Was asking for 3.33, most likely sold for that price

http://www.tf2outpost.com/trade/7951581 - Sold at 3.33

http://www.tf2outpost.com/trade/7916820 - Sold for a key

http://www.tf2outpost.com/trade/7889900 - Accepted an offer for a key

http://www.tf2outpost.com/trade/7855203 - Accepted an offer for a key

http://www.tf2outpost.com/trade/7724780 - Accepted an offer for around a key

http://www.tf2outpost.com/trade/7772002 - 1 Week later, no sales, looking for 4 ref

Yet another genuine whose demand has fallen; people are not so willing to pay 4 ref for these, as one can easily find one for a round 3-3.33. Pretty much all of the currently open trades for these things are asking for around 4 ref, however they are relatively new trades; I looked for some counter-proof, and here's what I could come up with:

http://www.tf2outpost.com/trade/6904976 - Most likely sold for around 3.33-3.66