Classifieds: http://backpack.tf/classifieds?item=Birdcage&quality=5&tradable=1&craftable=1&australium=-1&particle=19&killstreak_tier=0

Screenshot(s) of Classifieds:

http://imgur.com/QRNf9oq

<Sellers>

30 keys | http://backpack.tf/item/1395799109 | http://backpack.tf/u/76561198176125115 | Listed about a month ago [Bumped]

30 keys | http://backpack.tf/item/5090305975 | http://backpack.tf/u/76561198127938353 | http://www.tf2outpost.com/trade/28887692 | Listed about 9 hours ago

32 keys | http://backpack.tf/item/5028864224 | http://backpack.tf/u/76561198074924284 | Listed 4 months ago [Bumped]

http://www.tf2outpost.com/trade/28893243 - b/o: 32 keys (young)

Sold:

http://www.tf2outpost.com/trade/28890936

http://backpack.tf/profiles/76561198015384426#!/compare/1492819200/1492905600 - sold for Mega Strike Taunt: Most Wanted + 3 keys = 24 keys b/o

http://www.tf2outpost.com/trade/28888103

http://backpack.tf/profiles/76561198117542709#!/compare/1492732800/1492819200 - sold for 23 keys (quicksold)

http://www.tf2outpost.com/trade/28821156

http://backpack.tf/profiles/76561197982295876#!/compare/1488931200/1489104000 - sold for 23 keys (quicksold)

http://www.tf2outpost.com/trade/28856822

http://backpack.tf/profiles/76561197993989727#!/compare/1492300800/1492387200 - sold for Strange Specialized Killstreak Australium Medi Gun = 25 keys

http://backpack.tf/profiles/76561198095335435#!/compare/1488326400/1488499200 - sold for 30 keys

Credits to Marty Birdman