5 month old price, one sale for the low end but given a higher B/O with a "C/O" above 1.3 I'll take that B/O into consideration for the range.

Sold for 1 bud + 6 keys = ~1.3

http://www.tf2outpost.com/trade/18557806

B/O of 1.6 buds, has a C/O of a Terror Watt Bolted Birdcage (~1.4)

http://www.tf2outpost.com/trade/19533341

Owner is also a chronic relister, some of their previous B/Os are:

http://www.tf2outpost.com/trade/19512224 = 1.5, few days ago

http://www.tf2outpost.com/trade/19078404 = 1.5, 2-3 weeks ago

http://www.tf2outpost.com/trade/18760637 = 1.5, over 1 month ago

http://www.tf2outpost.com/trade/18238554 = 2 buds, around 2 months ago

B/O of 38 keys, open for 3 months

http://www.tf2outpost.com/trade/17158859