This needs a drop.

Classified ads at the time of posting:

Page 1 - http://m.imgur.com/U75Poma

Page 2 - http://m.imgur.com/iAXeEzX

http://backpack.tf/classifieds?item=Ambassador&quality=11&tradable=1&craftable=1&australium=1

1*14.89 keys

6*15 keys (1 has parts attached)

1*15.52 keys (Has Specialized Killstreak)

1*15.63 keys (Has Specialized Killstreak and parts attached)

1*15.89 keys (Has Specialized Killstreak)

9*16 keys (4 have Specialized Killstreak and 1 has parts attached)

Unsolds at 16 keys:

http://www.tf2outpost.com/trade/27516718 (~2 weeks)

http://www.tf2outpost.com/trade/27551117 (Has Specialized Killstreak, ~6 days)

http://www.tf2outpost.com/trade/27537110 (~1 week)

http://www.tf2outpost.com/trade/27565688 (Has Specialized Killstreak, ~2 days)

Unsold at 15.5 keys:

http://www.tf2outpost.com/trade/27493207 (Has Specialized Killstreak, ~2 weeks)

Sellers at 15 keys:

http://www.tf2outpost.com/trade/27572346 (Young)

http://www.tf2outpost.com/trade/27569067 (~1 day old)

http://www.tf2outpost.com/trade/27572186 (Young)

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