Sellers for 2 / 2.5 keys :

http://www.tf2outpost.com/trade/13125587 => 2 keys

http://www.tf2outpost.com/trade/12709500 => 2 keys (2 weeks)

http://www.tf2outpost.com/trade/13154596 => 2 keys 2 rec

http://www.tf2outpost.com/trade/12587284 => 2 keys 1 ref (2 weeks)

http://www.tf2outpost.com/trade/13146106 => 2 keys 2 ref

Unsuccessful sellers for 2,5 keys and more :

http://www.tf2outpost.com/trade/12704425 => 2 keys 3 ref (2 weeks old)

http://www.tf2outpost.com/trade/13017625 => 3 keys minus 1 ref (5 days old)

http://www.tf2outpost.com/trade/13063754 => 3 keys (3 days old)

http://www.tf2outpost.com/trade/11887512 => 3 keys (1 month old)

http://www.tf2outpost.com/trade/12090085 => 3 keys (1 month old)

http://www.tf2outpost.com/trade/12037154 => 18 ref (1 month old)

Buyers , just 1 page :

max is 2 keys => http://www.tf2outpost.com/trade/13148004