9 month old price and counter suggestion.

Sold for Australium SMG (~9 keys)

http://backpack.tf/profiles/76561198077770014?time=1427526000 (Before)

http://backpack.tf/profiles/76561198077770014?time=1427612400 (After)

Sold for 8 keys + Spec. Mackeral (~0.8 keys) + 19 ref (1 key, 19 ref at the time of sale) + Kringle Collection (~5 ref) = 10 keys

http://backpack.tf/profiles/76561198067581837?time=1427785200 (Before)

http://backpack.tf/profiles/76561198067581837?time=1427871600 (After)

http://steamcommunity.com/market/listings/440/Specialized%20Killstreak%20Holy%20Mackerel

Credit to Giang for pointing out this seller:

Selling at 11 keys for several days

http://www.tf2outpost.com/trade/25656859

But was selling at 11.5 keys for much longer previously

http://www.tf2outpost.com/trade/25054210

Currently up on classifieds at 10 keys though being a classified take it as you will

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