Classifieds at the time of posting: http://backpack.tf/classifieds?item=Firewall+Helmet&quality=6&tradable=1&craftable=1

http://i.imgur.com/mb6NTcO.png

1x at 1.66

1x at 1.77

1x at 1.88

2x at 2.00

Seller at 1.77(Poorly bumped, but supportive)

http://www.tf2outpost.com/trade/27511165

I would probably go with 1.77-1.88 here.

1.88 basically is no change from the current price but narrowing the range. I don't think that's appropriate to do based on an unsold. Anyways, it has sold and there are sellers at 1.66-1.77 anyways, so this should get a range regardless.