Sale at 5 ref:

http://www.tf2outpost.com/trade/27775704

http://puu.sh/mP9e8/a1debea7d7.png

Classifieds Sellers:

http://puu.sh/mP98C/c936c671a0.png

Classifieds Buyers:

http://puu.sh/mP99j/b3fdbfe249.png

Outpost Sellers:

3.66 ref:

http://www.tf2outpost.com/trade/27389026 - restocker, none in inventory. not using.

4 ref:

http://www.tf2outpost.com/trade/27776408 - young

http://www.tf2outpost.com/trade/27237860 - restocker, none in inventory

Every other seller is either selling as a set or doesn't have a price listed.

Excluded 3.66 from the range because the seller has none in his inventory, therefore, he is not selling. My only proof for 4 ref as of now is a young seller, so if it sells quickly, i'll have to re-suggest at 5 ref flat.