Within 2 days these things went up from ~4 ref to 5 ref on trade.tf, some people are selling it right now for 4 ref or even a bit less, not sure.

http://www.tf2outpost.com/trade/14984993 - Sold for 2 ref

http://www.tf2outpost.com/trade/14963189 - Sold for 2 ref

http://bazaar.tf/trade/474473 - Sold for 2.33

http://www.tf2outpost.com/trade/14958865 - Sold for 2.33

http://www.tf2outpost.com/trade/14978621 - Sold for 3 ref

http://www.tf2outpost.com/trade/14957546 - Sold for 3 ref

http://www.tf2outpost.com/trade/14946529 - Sold for 3 ref

Everything above seems to be instasells.

These solds are a bit old-ish but seem to still happen.

http://www.tf2outpost.com/trade/14971672 - Sold for 4 ref

http://www.tf2outpost.com/trade/14977400 - Sold(?) for 4 ref

http://www.tf2outpost.com/trade/14982398 - Sold for 4.33

http://www.tf2outpost.com/trade/14970623 - Sold for 4 ref

http://www.tf2outpost.com/trade/14982297 - Sold for 4.66

http://www.tf2outpost.com/trade/14964689 - Sold for 4.66

http://www.tf2outpost.com/trade/14982398 - Sold for 4.33

http://backpack.tf/classifieds/search/id/525734a24dd7b8217f8b456a

Currently 3 sellers withn 4-4.66, most of the classifieds is 5+

This seems to be a good starting point.