Counter.

Classified ads at the time of posting:

http://m.imgur.com/Wi5dAGC

http://backpack.tf/classifieds?item=Potassium+Bonnett&quality=6&tradable=1&craftable=1&australium=-1

1*12 keys (Painted Team Spirit)

1*12.31 keys

1*12.52 keys

1*12.67 keys

4*13 keys (3 are painted white)

Sales at 13 keys:

http://www.tf2outpost.com/trade/27849588

http://www.tf2outpost.com/trade/27849177 (Painted green)

Seller at 12 keys and 6 refined (~12.3 keys):

http://www.tf2outpost.com/trade/27827066 (~1 week old)

Seller at 12 keys:

http://www.tf2outpost.com/trade/27853871 (Painted team spirit, ~1 day old)

This is all I could find on Outpost that are valid at the time of posting this suggestion.