Ironically pricing this right now with a full moon outside...

Classifieds (As of 1 AM EST):

http://prntscr.com/5pu6kv 1 at 4 ref, 2 at 5 ref

There are no current sellers on Outpost at 4.66

Sellers under the current price:

http://www.tf2outpost.com/trade/24271776 4.33 ref

http://www.tf2outpost.com/trade/24479610 4.33 ref

Recent sales:

http://i.imgur.com/wigPGmU.png 5 ref (Credit to Eldric)

http://www.tf2outpost.com/trade/24151916 4.66 ref

With such a limited market, with 5 ref selling relatively easy, but 4.33 going unsold, 4.33 to 5 seems to be the most accurate range.

Well, the second seller has since sold, and the 4 ref seller and one of the two 5 refs sellers have since either sold or been removed fro the classifieds while no new sellers have popped up on either the classifieds or Outpost, so the range still looks pretty good.