It's so easy to get at 3.66 and even under, but i'll go for 3.66 flat.

http://backpack.tf/classifieds/search/mecha classifieds has 2 at 3.33 and 6 at 3.66

http://www.tf2outpost.com/trade/11428716 my trade, has offer of 3.66, 3.55 in items, 3.33 and 2.66

Selling for 3.66

http://www.tf2outpost.com/trade/11730891

http://www.tf2outpost.com/trade/11576152 unsold for 5 days

http://www.tf2outpost.com/trade/11734173

http://www.tf2outpost.com/trade/11716264

Unsold at 4

http://www.tf2outpost.com/trade/11607516 4 days

http://www.tf2outpost.com/trade/11438234 a week

http://www.tf2outpost.com/trade/11610732 4 days

http://www.tf2outpost.com/trade/11658030 2 days

http://www.tf2outpost.com/trade/11692212 a day

http://www.tf2outpost.com/trade/11681212 a day

http://www.tf2outpost.com/trade/11684087 a day

Selling for under 3.66

http://www.tf2outpost.com/trade/11717008 3.33

http://www.tf2outpost.com/trade/11610743 3.33, got added but still has it in his bp

Selling for 3.77, painted drab tincture

Basically its really easy to get for 3.66, so 4 ref shouldnt be in the range anymore, even though the price was only changed yesterday